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The production of pulp and paper from recycled paper generates significant quantities of deinking paper sludge (DPS). This sludge contains a significant amount of organic matter (36%) as well as heavy metals such as Pb, Zn, and Cr. In this work, the incorporation of DPS (0%, 8%, 10%, and 12%) in the manufacture of clay bricks leads to valorization of this waste by showing that two of its contents considered problematic (organic matter and heavy metals) have several positive effects. It was found that the organic parts were transformed into pores after brick firing (850°C), which improved thermal insulation while keeping mechanical resistance in conformity with usual standards. For the heavy metals, which make DPS a hazardous waste, a leaching test was employed. The results show that these metals were trapped in the ceramic matrix after the firing of bricks at a high temperature, resulting in a final product that was not dangerous. Other tests were carried out on bricks with DPS to evaluate density, water absorption, shrinkage, loss on ignition, porosity, and microstructure in order to characterize this new product. It was concluded that DPS can be used in clay bricks as an asset for the formation of pores to enhance thermal insulation. The addition of DPS can be optimized at 10% to comply with the standard and not exceed the required values for shrinkage, water absorption, and loss on ignition. [ABSTRACT FROM AUTHOR]

The paper and paper products sector is a crucial component of the Turkish economy, characterized by significant interactions with various other sectors. Türkiye imports substantial amounts of paper, playing a vital role in the growth and sustainability of this sector. Accurate import forecasting is essential for strategic planning and resource management. This study aims to forecast the imports of the Turkish paper sector for the period from April 2023 to March 2024 using two artificial neural network (ANN) models: Multilayer Perceptron (MLP) and Radial Basis Function (RBF). The dataset, obtained from the Turkish Statistical Institute (TurkStat), covers 219 months of data from 2005 to 2023. The dependent variable is Türkiye’s monthly import value of paper and paper products, while the independent variables include the monthly average US Dollar exchange rate, monthly imports of Türkiye, the Manufacturing Industry Production Index, the Paper Production Index, and the monthly exports of paper and paper products from Türkiye. The MLP model forecasts that the monthly imports of paper and paper products will range between 270 to 300 million USD, while the RBF model predicts values between 268 and 321 million USD. These findings underscore the efficacy of ANNs in providing accurate and reliable forecasts. This study addresses a gap in the literature by applying ANN methods to forecast imports in the paper and paper products sector, presenting a novel approach that can assist companies in making better-informed decisions regarding inventory management, production planning, and marketing strategies. By leveraging the advanced computational power and pattern recognition capabilities of ANNs, the study aims to enhance the strategic planning processes in the paper and paper products industry. The traditional methods often used in trade data analysis and forecasting are limited in capturing the complex and non-linear relationships present in economic data. This study's application of ANNs offers a significant advancement by utilizing models that can better handle such complexities. The accuracy of the MLP and RBF models highlights their potential as valuable tools for economic forecasting, providing insights that are crucial for optimizing supply chain operations and improving market responsiveness. The results indicate that companies can achieve better operational performance and increased customer satisfaction by effectively forecasting future import requirements. The originality of this study lies in its methodological approach, utilizing ANN models to forecast import values in a sector where traditional methods have been predominant. This innovative approach not only contributes to the existing body of knowledge but also offers practical applications for businesses within the sector. The detailed analysis of the data, combined with the robust modeling techniques employed, provides a comprehensive framework for understanding the dynamics of paper imports and making strategic decisions based on accurate predictions. In conclusion, the study demonstrates the significant success of artificial neural networks in predicting import values for the Turkish paper and paper products sector. The findings provide valuable information that can aid companies in strategic planning, enhancing their ability to manage inventory, plan production, and develop effective market strategies. The research contributes to the literature by filling a gap with its innovative approach, offering new perspectives and practical applications for improving decision-making processes in the industry. [ABSTRACT FROM AUTHOR]

Background: As the demand for digital dentistry constantly increases, digital devices are gradually replacing conventional methods of recording occlusal contacts. The study aimed to assess the inter-rater reliability of occlusal contact point detection using 40 μm articulating paper, Medit i700, and OccluSense and to compare the distribution of occlusal contacts using the articulating paper and intraoral scanner. Material and Methods: The study included 25 participants aged 20 to 30 (13 women and 12 men). Photographs of contact points were taken and marked in maximum intercuspal position (MIP), in protrusive and laterotrusive movements, on working and non-working sides using 40 μm articulating paper and digital devices. The Cohen's Kappa coefficient assessed the inter-rater reliability. The Wilcoxon signed-rank test was used to compare dependent groups, articulating paper, and Medit i700. Results: The Cohen's Kappa index showed that almost perfect agreement was achieved with 40 μm articulating paper. Compared to Medit i700, the 40 μm articulating paper showed an increased mean number of contacts per tooth, except for the third molars. Conclusions: The 40 μm articulating paper has detected more overall contacts than the digital devices, particularly in the posterior areas. An ideal method for registering occlusal contacts has not been established yet. [ABSTRACT FROM AUTHOR]

Excessive copper (Cu2+) causes adverse effects on human health and the ecological environment. Traditional methods for detecting Cu2+ have drawbacks such as high detection costs, complex operating conditions, and being time consuming. Therefore, there is an urgent need to develop simple detection methods to better meet specific health and environment quality needs. In this work, a paper-based fluorescence sensor was prepared (herein referred to as the as-prepared method) by immersing filter paper in aqueous polyethyleneimine (PEI) solution, and its potential use in Cu2+ detection was investigated. The results showed that the as-prepared paper samples, with fluorescence properties obtained by aggregation-induced luminescence of PEI, have selective recognition of Cu2+ based on the internal filtration effect, and the lowest detection limit is 0.03 μM. In addition, the relative error of this method is in the range of 1.80~2.23%, which is relatively comparable to the national standard method (0.63~630 μM), demonstrating high accuracy. Therefore, paper-based sensors with a simple preparation method have potential applications in the detection of Cu2+ in water. [ABSTRACT FROM AUTHOR]

Simple Summary: This study emphasizes the significance of appropriate air-drying times in toxicity bioassays to accurately establish sublethal concentrations and discriminating concentrations for resistance detection in mosquitoes to a highly volatile pyrethroid, namely, transfluthrin. The high-throughput screening system toxicity bioassay study demonstrated consistent dose-dependent responses in susceptible mosquito populations. Our findings emphasize the importance of accurate susceptibility testing to facilitate early resistance detection. The air-drying duration significantly affected the efficacy of transfluthrin: after drying for 24 h, the concentration needed to achieve the same level of efficacy was 2.8 times higher compared to the concentration needed after 1 h of drying. This is the first study to evaluate spatial repellents using a high-throughput screening system toxicity bioassay, yielding precise sublethal concentrations and discriminating concentrations for varying air-drying times of transfluthrin-treated filter papers. The study underscores the importance of early detection of resistant mosquito populations and emphasizes the need to optimize air-drying durations in toxicity bioassays. Selecting the right concentrations and assessing behavioral responses are crucial for developing effective mosquito control strategies with spatial repellents. This research enhances our understanding of resistance dynamics and provides guidance for practical implementation in vector control programs. Increasing temperature can enhance the geographical spread and behavior of disease vector mosquitoes, exposing vulnerable populations to Aedes-borne viruses and infections. To address this risk, cost-effective and sustained intervention vector control tools are required, such as volatile pyrethroid spatial repellents. This study used a high-throughput screening system toxicity bioassay to determine the discriminating concentrations of transfluthrin-treated filter papers with variable air-drying times exposed to pyrethroid-susceptible Aedes aegypti mosquitoes. At the highest transfluthrin concentration (0.01706%), a significant reduction in mosquito mortality was observed in filter papers air-dried for 24 h compared to those air-dried for 1 h (odds ratio = 0.390, p < 0.001, 95% confidence interval: 0.23–0.66). Conversely, no significant difference in mortality was found between filter papers air-dried for 1 h and those air-dried for 12 h (odds ratio = 0.646, p = 0.107, 95% confidence interval: 0.38–1.10). The discriminating concentration was 2.8-fold higher for transfluthrin-treated filter papers air-dried for 24 h than it was for papers air-dried for 1 h, and it increased 5-fold from 1 h to 336 h of air-drying. These results show that the optimal air-drying period of transfluthrin-treated filter paper is critical, as higher discriminating concentration values may lead to underestimations of insecticide resistance. The instability of transfluthrin-treated papers necessitates the use of the World Health Organization (WHO) bottle bioassay, which is the preferred method for determining mosquito susceptibility to volatile insecticides. [ABSTRACT FROM AUTHOR]

Nanorod structures exhibit a high surface-to-volume ratio, enhancing the accessibility of electrolyte ions to the electrode surface and providing an abundance of active sites for improved electrochemical sensing performance. In this study, tetragonal α-MnO2 with a large K+-embedded tunnel structure, directly grown on microfibrous carbon paper to form densely packed nanorod arrays, is investigated as an electrocatalytic material for non-enzymatic glucose sensing. The MnO2 nanorods electrode demonstrates outstanding catalytic activity for glucose oxidation, showcasing a high sensitivity of 143.82 µA cm−2 mM−1 within the linear range from 0.01 to 15 mM, with a limit of detection (LOD) of 0.282 mM specifically for glucose molecules. Importantly, the MnO2 nanorods electrode exhibits excellent selectivity towards glucose over ascorbic acid and uric acid, which is crucial for accurate glucose detection in complex samples. For comparison, a gold electrode shows a lower sensitivity of 52.48 µA cm−2 mM−1 within a linear range from 1 to 10 mM. These findings underscore the superior performance of the MnO2 nanorods electrode in both sensitivity and selectivity, offering significant potential for advancing electrochemical sensors and bioanalytical techniques for glucose monitoring in physiological and clinical settings. [ABSTRACT FROM AUTHOR]

Flexible paper-based materials play a crucial role in the field of flexible electromagnetic shielding due to their thinness and controllable shape. In this study, we employed the wet paper forming technique to prepare carbon fiber paper with a thickness gradient. The electromagnetic shielding performance of the carbon fiber paper varies with the ladder-like thickness distribution. Specifically, an increase in thickness gradient leads to higher reflectance of the carbon fiber paper. Within the X-band frequency range (8.2–12.4 GHz), reflectivity decreases as electromagnetic wave frequency increases, indicating enhanced penetration of electromagnetic waves into the interior of the carbon fiber paper. This enhancement is attributed to an increased fiber content per unit area resulting from a greater thickness gradient, which further enhances reflection loss and promotes internal multiple reflections and scattering effects, leading to increased absorption loss. Notably, at a 5 mm thickness, our carbon fiber paper exhibits an impressive average overall shielding performance, reaching 63.46 dB. Moreover, it exhibits notable air permeability and mechanical properties, thereby assuming a pivotal role in the realm of flexible wearable devices in the foreseeable future. [ABSTRACT FROM AUTHOR]

The mineralization of inorganic components in paper sludge offers potential for their re-use in various fields. This study synthesized carbonates based on the minerals present in paper sludge and aimed to investigate the control of particle size distribution and particle shape of the synthesized carbonates. First, the physicochemical and thermal properties of paper mill sludge and ash were evaluated using a spectrophotometer, XRF, and TGA. Paper sludge ash was obtained by incinerating the paper sludge, followed by a carbonation reaction using CO2 gas injection and pH neutralization to produce recycled fillers. The average particle size, crystal lattice structure, and morphology of the recycled fillers were analyzed using a particle size analyzer, XRD, and FE-SEM. The results indicate that the recycled filler produced from coating paper sludge exhibited similar brightness and morphology to conventional paper-based fillers, suggesting its potential to replace commercial PCC (Precipitated Calcium Carbonate). In contrast, the recycled filler manufactured using old corrugated container mill sludge was deemed unsuitable due to its low hydration activity. [ABSTRACT FROM AUTHOR]

Pretreated carboxymethylated nanofibrillated cellulose (CM-NFC) was tested as a strength enhancer for specialty paper, such as banknotes made from cotton linter mixed pulp (CLMP). The pretreatment agent was cationic poly(acrylamide) (C-PAM). The CM-CMF prototype was supplied by a Korean manufacturer. Laboratory tests and pilot trials were performed to evaluate the strength enhancement of banknotes incorporated with surface-modified CM-NFC and determine the process problems encountered in a pilot paper machine. The CM-NFC was surface modified with 0.1% C-PAM without any agglomerates. The prepared laboratory handsheets had high paper strength, which was attributed to the higher nanofibril content of surface-modified CM-NFC compared with that of unmodified CM-NFC. Pilot trials showed that the incorporation of 3% surface-modified CM-NFC was highly effective in promoting the strength of banknote without low retention and drainability on the wet-end part of the pilot paper machine. Therefore, surface-modified CM-NFC at a controlled dosage could be used as a strength enhancer for specialty paper without incurring serious problems in a paper mill. [ABSTRACT FROM AUTHOR]

Grease-proof paper is an energy-demanding paper product to manufacture, especially during refining and dewatering. Increases in energy efficiency in either stage could result in major savings. This article investigates the potential gains with addition of a stepwise progression vacuum suction box to the forming section during production. For both a lighter, 50 g/m², and a heavier paper grade, 100 g/m², with a pulpdrainability of 86 °SR, a stepwise progression vacuum suction box in four steps would result in increased dryness, simultaneously with decreased energy expenditure. The observed effects were higher for the lower basis weight paper (50 g/m²). Both basis weights experienced clogging of the forming fabric due to the high degree of refining. This adversely affected the dewatering rate, decreasing the amount of air pulled through the paper even when increasing the vacuum pressure. When a stepwise progression suction box in four steps was compared to a single vacuum suction box, there was a 14% increase in dryness for lighter paper, over an equal energy consumption, measured as amount of air pulled through the paper. For the 100 g/m² paper, the increase in dryness was 3% compared to the 50 g/m² paper run over a single vacuum suction box. The results show great promise for energy savings when utilizing stepwise progression suction box dewatering for grease-proof paper production. [ABSTRACT FROM AUTHOR]

As air pollution escalates, the need for air filters increases. It is better that the filters used be based on natural fibers, such as non-wood fibers, which cause low damage to the environment. However, the short fiber lengths, low apparent densities, and high volumes of non-wood materials can make it challenging to prepare filter paper with the required mechanical and physical properties. In that context, this study focused on utilizing bamboo fibers to fabricate filter paper by employing the anthraquinone soda pulping method. The pulp underwent bleaching and oxidation processes, with the incorporation of cationic starch (CS) and polyvinyl alcohol (PVA) to enhance resistance properties, resulting in the creation of handmade filter papers. The findings revealed that the tear, burst, and tensile strength of filter paper increased with the oxidation and addition of CS and PVA. Air permeability increased with addition of PVA and combination of CS and PVA. FTIR demonstrated the conversion of hydroxyl groups in cellulose chains to carboxyl groups due to oxidation. SEM images illustrated alterations in the fiber structure post-oxidation treatment, with CS reducing pores while PVA and the CS-PVA combination enlarged pore size and enhanced porosity. The BET surface area surface area expanded with oxidation and the addition of the CS-PVA blend, indicating heightened filter paper porosity. Notably, the combined inclusion of CS and PVA not only augmented mechanical strength but also increased porosity while maintaining pore size. [ABSTRACT FROM AUTHOR]

Objectives: Endoscopic ultrasound‐guided tissue acquisition (EUS‐TA) is used for pathological diagnosis and obtaining samples for molecular testing, facilitating the initiation of targeted therapies in patients with pancreatic cancer. However, samples obtained via EUS‐TA are often insufficient, requiring more efforts to improve sampling adequacy for molecular testing. Therefore, this study investigated the use of oil blotting paper for formalin fixation of samples obtained via EUS‐TA. Methods: This prospective study enrolled 42 patients who underwent EUS‐TA for pancreatic cancer between September 2020 and February 2022 at the Osaka International Cancer Institute. After a portion of each sample obtained via EUS‐TA was separated for routine histological evaluation, the residual samples were divided into filter paper and oil blotting paper groups for analysis. Accordingly, filter paper and oil blotting paper were used for the formalin fixation process. The total tissue, nuclear, and cytoplasm areas of each sample were quantitatively evaluated using virtual slides, and the specimen volume and histological diagnosis of each sample were evaluated by an expert pathologist. Results: All cases were cytologically diagnosed as adenocarcinoma. The area ratios of the total tissue, nuclear, and cytoplasmic portions were significantly larger in the oil blotting paper group than in the filter paper group. The frequency of cases with large amount of tumor cells was significantly higher in the oil blotting paper group (33.3%) than in the filter paper group (11.9%) (p = 0.035). Conclusions: Oil blotting paper can increase the sample volume obtained via EUS‐TA on glass slides and improve sampling adequacy for molecular testing. [ABSTRACT FROM AUTHOR]

A pre-treatment process was evaluated in this work for wastewater from paper recycling using microwave technology followed by rapid precipitation of contaminants through centrifugation. Artificial neural networks (ANNs) were used to analyze and optimize the turbidity values. Thirty experimental runs were utilized including microwave (MW) power, duration, centrifuge time, and centrifuge speed as input variables, generated by the Central Composite Full Design (CCFD) approach. The experimental turbidity ranged from 8.1 to 19.7 NTU, while predicted values ranged from 8.4 to 19.7 NTU by ANN. The ANN model showed a robust prediction performance with low mean squared error values during training and testing. Moreover, high R² values showed a remarkable agreement between the experimental observations and ANN predictions. The results obtained from the input values (A:150.00, B:60.00, C:15.00, D:30.00) of sample 2, which gave the lowest turbidity value, showed the most removal of pollution. The results obtained from the input values (A:250.00, B:60.00, C:7.00, D:20.00) of sample 30, which gave the highest turbidity value, showed the least removal of pollution. The results showed that increasing RPM and time of the centrifugation process significantly affected the removal of pollution in wastewater. [ABSTRACT FROM AUTHOR]

This study examined the possibility of using various types of waste paper—used newsprint (NP), used lightweight coated paper (LWC), used office paper (OP), and used corrugated cardboard (CC)—for the removal of anionic dyes, Acid Red 18 (AR18) and Acid Yellow 23 (AY23), and cationic dyes, Basic Violet 10 (BV10) and Basic Red 46 (BR46), from aqueous solutions. The scope of this research included the characterization of sorbents (FTIR, SEM, BET surface area, porosity, pHPZC, effectiveness of water coloration), determination of pH effect on the effectiveness of dye sorption, sorption kinetics (pseudo-first-order model, second-order model, intraparticular diffusion model), and the maximum sorption capacity (Langmuir models and Freundlich model) of the tested sorbents. The use of waste paper materials as sorbents was found to not pose any severe risk of aquatic environment contamination. AR18, AY23, and BV10 sorption intensities were the highest at pH 2, and that of RB46 at pH 6. The waste paper sorbents proved particularly effective in removing cationic dyes, like in the case of, e.g., NP, which had a sorption capacity that reached 38.87 mg/g and 90.82 mg/g towards BV10 and BR46, respectively, and were comparable with that of selected activated carbons (literature data). [ABSTRACT FROM AUTHOR]

In this study, the integration of paper industry waste with high cellulose content into biocomposites of polylactic acid (PLA), a widely used biobased polymer material, was investigated. The PLA/waste biocomposite samples (0–25 wt.%) were manufactured using the extrusion and injection moulding techniques. The mechanical test results showed improvements in terms of tensile properties and a decrease in impact strength as the percentage of residue increased. The melting temperature decreased, and the crystallinity increased in all biocomposites according to the Differential Scanning Calorimetry (DSC) analysis. Water absorption increased proportionally with the percentage of residue, attributed to the higher cellulose content in the biocomposites, determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques. The scanning electron microscopy (SEM) fracture analysis demonstrated effective reinforcement–matrix cohesion, supporting the previously observed behaviour of the analysed materials. This work highlights the potential of using waste from the paper industry as reinforcement in PLA matrices, opening new perspectives for sustainable applications in the framework of the manufacture of composite materials. [ABSTRACT FROM AUTHOR]

Electronic paper displays rely on electrokinetic effects in nonpolar solvents to drive the displacement of colloidal particles within a fluidic cell. While Electrophoresis (EP) is a well-established and frequently employed phenomenon, electro-osmosis (EO), which drives fluid flow along charged solid surfaces, has not been studied as extensively. We hypothesize that by exploiting the interplay between these effects, an enhanced particle transport can be achieved. In this study, we experimentally investigate the combined effects of EP and EO for colloidal particles in non-polar solvents, driven by an electric field. We use astigmatism micro-particle tracking velocimetry (A- μ PTV) to measure the motion of charged particles within model fluidic cells. Using a simple approach that relies on basic fluid flow properties we extract the contributions due to EP and EO, finding that EO contributes significantly to particle transport. The validity of our approach is confirmed by measurements on particles with different magnitudes of charge, and by comparison to numerical simulations. We find that EO flows can play a dominant role in the transport of particles in electrokinetic display devices. This can be exploited to speed up particle transport, potentially yielding displays with significantly faster switching times. Interplay of electrokinetic effects : Driven by the applied electric field, both electro-osmosis (EO, top left), which drives a flow along the surfaces of the fluidic cell, and electrophoresis (EP, top right), which drives a migration of particles relative to the background liquid, occur in our system. A typical example of the resultant particle velocity field (bottom) illustrates the important role of EO on particle transport in the fluidic cell. • Studied electrokinetics of particles in nonpolar solvent using astigmatism micro-PTV. • Both electrophoresis (EP) and electro-osmosis (EO) play important roles. • Combination of EO and EP could be exploited in faster switching e-paper displays. [ABSTRACT FROM AUTHOR]

The increase in energy valorization of paper sludge and biomass waste through incineration results in a rise in waste paper fly ash (WPFA), often perceived as hazardous and requiring specific treatment. In this study, natural carbonation technology at a pilot scale was employed to mitigate the hazardous nature of WPFA by enhancing the stabilization of metal and metalloid trace elements (MMTE), particularly barium (Ba) and lead (Pb) leaching. Natural carbonation of WPFA was found to be optimal at a water/solid ratio of 0.3 L/kg under natural temperature and humidity conditions. Batch leaching tests based on thermodynamic equilibrium were used to assess MMTE solubility concerning pH in both non-carbonated and carbonated WPFA at natural pH. After 7 days of natural carbonation, the leaching concentration of Ba and Pb was below the legal limit in France. The concentration of Ba and Pb in carbonated samples decreased by 98.5% and 98%, respectively. Analyses using thermogravimetry, X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy demonstrated the increased formation and quantity of calcite (CaCO3) with longer carbonation times, along with the formation of new minerals as BaCO3 and PbCO3, confirming the immobilization of these elements post-carbonation. The leaching behavior and release potential of carbonated WPFA were further evaluated using the four-stage sequential extraction procedure proposed by the European Commission's Bureau of Reference (BCR). The speciation of Ba and Pb shifted significantly from the soluble substance (F1) at 17.6% and 14.8%, respectively, to the carbonate fraction (F2) at 0.49% and 0.02% after 90 days of carbonation. The percolation water collected during the carbonation process adheres to discharge standards into the sea. [ABSTRACT FROM AUTHOR]

The lifespan of an electrical transformer, primarily determined by the condition of its solid insulation, is well known under various operating conditions when mineral oil is the coolant in these machines. However, there is a trend toward replacing this oil with biodegradable fluids, especially esters; therefore, an understanding of the ageing of solid insulation with these fluids is essential. Currently available data do not allow for the selection of the best ester among those available on the market, as each study applies different conditions, making it impossible to compare results. Thus, this paper analyses the degradation of Kraft and Thermally Upgraded Kraft papers with the following five most promising commercial esters: sunflower, rapeseed, soybean, palm, and synthetic. The materials underwent accelerated thermal ageing at 130, 150, and 170 °C, and the integrity of the papers was evaluated through their polymerisation degree and the obtaining of the degradation kinetic models. The wide range of materials studied in this work, which were subjected to the same treatments, allows for a comparison of the esters, revealing significant differences in the impact of the alternative fluids. Sunflower, rapeseed, and soybean esters provided the best paper protection, i.e., the degree of polymerisation of Kraft paper in the tests at 150 °C decreased by 71% with these fluids, compared to the 83% reduction with mineral oil, 79% reduction with palm ester, and 75% reduction with synthetic ester. Furthermore, different kinetic models were obtained to predict the degradation; it was concluded that the Emsley model provides the best fit. Additionally, it was found that the behaviour of a dielectric fluid with one type of paper cannot be extrapolated, which is only noticeable in broad-scope studies. [ABSTRACT FROM AUTHOR]

The pulp and paper industry is under increasing pressure to reduce its energy consumption and carbon footprint. This study examines the feasibility of integrating high-temperature heat pumps (HTHP) into tissue paper production to enhance energy efficiency and decarbonization. Focusing on the energy-intensive drying process, the study uses data from a typical tissue paper mill to simulate and optimize an HTHP system producing four tons per hour of nine-bar saturated steam. It also addresses necessary modifications for HTHP integration applicable across the sector. Various refrigerants were analyzed, achieving a maximum coefficient of performance (COP) of 2.01. Results showed that HTHP can reduce energy consumption and emissions by up to 17% and 40%, respectively, based on the European electricity mix. Although steam production costs increase by 55% compared to fossil fuel-based systems, HTHP is more cost-effective than direct electric resistance heating, which raises costs by 196%. With a CO2 price of EUR 100/t, HTHP offers a 12% cost reduction. However, without public funding, capital expenditures may be unsustainable in many regions, though viable in countries with favorable gas and electricity price differentials. The paper underscores the need for advancements in HTHP technology and cost reductions, emphasizing industry adaptation for seamless HTHP integration. [ABSTRACT FROM AUTHOR]

We previously used a grinder to prepare cellulose nanofibers (CNFs) that were then added to pulp to improve the wet strength of paper, with subsequent alkali treatment further improving its wet tensile strength. However, mass production of CNF using ultra-fine grinders is not feasible; moreover, fabricating paper sheets by first preparing CNFs and adding them to pulp is a complex process. Therefore, in this study, we directly fibrillated pulp using a refiner instead separately preparing CNFs, with the refined pulp used to make paper sheets, thereby simplifying the process. The resulting dried sheets were subsequently treated with 8 and 16 wt% NaOH, after which the co-reinforcing effect of the refiner and NaOH treatments on the wet tensile strength of paper was examined. Unexpectedly, wet tensile strength of 39 and 45 MPa was achieved. These values are higher than values obtained using the CNFs and NaOH treatment, and comparable to the dry strength of untreated and unrefined pulp sheet. Moreover, the dewatering time of the refiner-treated pulp was significantly shorter than that of the CNF-mixed pulp, which reduces the time required to prepare paper. This study demonstrated that refiner-treated pulp is more suitable than CNF-mixed pulp for improving paper wet strength. [ABSTRACT FROM AUTHOR]

The effect of shredded waste office paper was considered when producing one-layered particleboard. Five different mixing ratios of shredded waste office paper/wood particles were used (0/100, 25/75, 50/50, 75/25, and 100/0) and two amounts of urea formaldehyde (UF) resin (10% and 15%). The boards were tested for their physical and mechanical properties, including modulus of elasticity (MOE), bending strength (MOR), and internal bond (IB) strength, in accordance with the European Norm (EN) standards. All properties of the boards were found to be improved via increasing the resin content. The 15% UF-bonded board with 100% wood particles had the highest MOR, whereas the board containing 100% wastepaper for 15% UF had the highest MOE. However, there was no statistical difference between the board types. Although increasing wastepaper content in the board negatively affected the IB, the usage of wastepaper up to 25% was shown to be acceptable as a raw material in the production of particleboard. None of the prepared boards met the EN 312 (1999) requirements for thickness swelling. The boards made from shredded waste office paper were more suitable for dry and indoor use. [ABSTRACT FROM AUTHOR]

In the realm of electrochemical nitrite detection, the potent oxidizing nature of nitrite typically necessitates operation at high detection potentials. However, this study introduces a novel approach to address this challenge by developing a highly sensitive electrochemical sensor with a low reduction detection potential. Specifically, a copper metal nanosheet/carbon paper sensitive electrode (Cu/CP) was fabricated using a one-step electrodeposition method, leveraging the catalytic reduction properties of copper's high occupancy d-orbital. The Cu/CP sensor exhibited remarkable performance in nitrite detection, featuring a low detection potential of −0.05 V vs. Hg/HgO, a wide linear range of 10~1000 μM, an impressive detection limit of 0.079 μM (S/N = 3), and a high sensitivity of 2140 μA mM−1cm−2. These findings underscore the efficacy of electrochemical nitrite detection through catalytic reduction as a means to reduce the operational voltage of the sensor. By showcasing the successful implementation of this strategy, this work sets a valuable precedent for the advancement of electrochemical low-potential nitrite detection methodologies. [ABSTRACT FROM AUTHOR]

The emphasis on traditional hand-drawn compass and straight-edge geometrical constructions has been reduced in the core narrative of most current curricula. In response to this trend, this paper presents a virtual toolkit for producing precision geometrical figures within the popular note-taking app, NotabilityTM. These graphical procedures employ the app’s stylus-based input and shape tools (for lines, circles, and squares) to offer a modern take on classical geometrical construction. These procedures are adaptations of familiar textbook methods, necessary because the app’s circle-drawing tool behaves differently from a standard compass. Beyond the familiar canon of elementary Euclidean constructions, such as angle bisectors and perpendiculars, these tools are also used to sketch examples of sangaku diagrams from original 19th-century Japanese temple geometry problems. That such precision figures can be created within a popular tablet app is a rallying call to geometers; the art and craft of traditional manual constructions need not go extinct and can continue to be nurtured in this age of digital paper. [ABSTRACT FROM AUTHOR]

A highly sensitive sensor based on carbon fiber paper modified with a shungite–copper formazanate composite is presented for the voltammetric determination of lidocaine. The synthesized organometallic complex, composite, and modified electrode are characterized by infrared spectroscopy, high-resolution mass spectrometry, elemental analysis, scanning electron microscopy, and cyclic and linear sweep voltammetry. The twofold increase in the current of the lidocaine oxidation peak on the modified electrode compared to the unmodified one is associated with the sensitizing effect of the composite modifier, which is due to an increase in the electroactive area and the number of lidocaine binding sites on the electrode surface. The sensor exhibits a wide dynamic range from 2 to 2120 µM with a low limit of detection of 0.18 µM lidocaine and high sensitivity of 0.755 µA/V µM. The interelectrode and intraelectrode repeatability of the analytical signal do not exceed 3.5%. The sensor response is stable within three weeks. The developed sensor was used for the determination of lidocaine in pharmaceuticals. The results of an analysis of real samples demonstrated good reproducibility (RSD ≤ 5.5%) and recovery (98–102%). [ABSTRACT FROM AUTHOR]

Background: Efficient monitoring of glucose concentration in the human body necessitates the utilization of electrochemically active sensing materials in nonenzymatic glucose sensors. However, prevailing limitations such as intricate fabrication processes, lower sensitivity, and instability impede their practical application. Herein, ternary Cu-Co-Ni-S sulfides nanoporous network structure was synthesized on carbon fiber paper (CP) by an ultrafast, facile, and controllable technique through on-step cyclic voltammetry, serving as a superior self-supporting catalytic electrode for the high-performance glucose sensor. Results: The direct growth of free-standing Cu-Co-Ni-S on the interconnected three-dimensional (3D) network of CP boosted the active site of the composites, improved ion diffusion kinetics, and significantly promoted the electron transfer rate. The multiple oxidation states and synergistic effects among Co, Ni, Cu, and S further promoted glucose electrooxidation. The well-architected Cu-Co-Ni-S/CP presented exceptional electrocatalytic properties for glucose with satisfied linearity of a broad range from 0.3 to 16,000 μM and high sensitivity of 6829 μA mM− 1 cm− 2. Furthermore, the novel sensor demonstrated excellent selectivity and storage stability, which could successfully evaluate the glucose levels in human serum. Notably, the novel Cu-Co-Ni-S/CP showed favorable biocompatibility, proving its potential for in vivo glucose monitoring. Conclusion: The proposed 3D hierarchical morphology self-supported electrode sensor, which demonstrates appealing analysis behavior for glucose electrooxidation, holds great promise for the next generation of high-performance glucose sensors. [ABSTRACT FROM AUTHOR]

The recyclable paper based on photochromic materials not only reduces the pollution in the paper manufacture process, but also reduces the pollution caused by the use of ink, which receives wide attention. In this paper, a series of phosphomolybdic acid–phosphotungstic acid/ZnO/polyvinylpyrrolidone (PMoA-PWA/ZnO/PVP) hybrid films, which had different ratio of PMoA/PWA, was prepared by the ultrasonic composite method. The results indicated that the hybrid film prepared when the ratio of PMoA to PWA was 3 had the best photochromic performance. In this system, ZnO was the photosensitizer, while PMoA/PWA was the chromophore. The photochromic mechanism of the PMoA-PWA/ZnO/PVP hybrid film was based on the photogenerated electron transfer mechanism. ZnO generated photoelectron under the excitation of visible light, then PMoA and PWA obtained the photoelectron and produced photoreduction reaction to generate heteropolyblue. The visible light photochromic paper was prepared by loaded PMoA-PWA/ZnO/PVP hybrid film (A3) on A4 paper. Application tests showed that the prepared paper had extremely stable, excellent and reversible visible light photochromic properties, whether it was printing patterns or words, and could replace ordinary paper to realize the reuse of paper. [ABSTRACT FROM AUTHOR]

Novel highly foldable HAp ceramic paper with fire retardancy but without fiber was fabricated via novel non-solvent displacement nonaqueous precipitation strategy. The obtained HAp ceramic paper, characterized by highly smooth and glossy, is characterized via X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), curlability test, moisture absorbency and Pb2+ removal performance test. The results show that the ceramic paper is very straight, uniform, and smooth with high curlability and low moisture absorption. No fiber is detected in the ceramic paper. No defect is either detected except for at the edge area. The HAp ceramic paper is grown along the (002) crystal plane of the hydroxyapatite phase from hexagonal plate like single crystal sheets. The ceramic paper loaded for four times has formed a clear four-layer-structured, with a total thickness of about 832 nm. The thickness of each layer is very uniform, with an average thickness of about 208 nm per layer. HAp ceramic paper has excellent Pb2+ ions removal performance, curling performance, moisture absorption performance and flame retardant performance. These performances confirm this novel HAp ceramic paper has superior properties over the traditional ceramic paper with fibers and shows great application prospect in various fields. [ABSTRACT FROM AUTHOR]

Paper has been in common use for centuries and plays an important part in our daily life. The paper making process is a complex process that comprises various steps. Thus, a component's breakdown or failure can lead to poor system performance or in system failure. Therefore, a comprehensive system analysis is necessary for improved performance. In this research, the authors have examined the operation and performance of a paper mill, in order to gauge and enhance its performance. The reliability, availability, maintainability and dependability (RAMD) of the system are analysed. Appropriate mathematical models are developed on the basis of Markov birth-death processes to analyse production under steady-state conditions. The whole system is made up of six subsystems. Measures of the reliability, availability, maintainability, dependability, mean time between failures (MTBF), mean time to failure (MTTF), and dependability ratio are evaluated for the entire system. [ABSTRACT FROM AUTHOR]

The filter paper (FP) method, a cost-effective, versatile, and convenient approach, has found extensive application in analyzing fine-grained soils, enabling the successful measurement of a broad spectrum of total and matric suctions. However, using the FP method in sand with a limited range of suction profiles has been notably underrepresented in the existing literature. Therefore, this study investigated the applicability of the contact FP method in establishing soil water retention curves (SWRCs) using five distinct FP calibration curves for 10 poorly graded sands. Among these calibration curves, the one presented by Chandler yielded the highest suction values, which were followed by those of ASTM. Furthermore, the FP results were subjected to fitting with a mathmatical model, which led to the observation that the overall trends in the obtained SWRCs displayed smooth sigmoidal shapes, resulting in a complete and coherent SWRCs. The SWRC results of five sand samples were assessed through validation against the hanging column technique (HCT) results, indicating a high degree of concordance and affirming the suitability of the FP method for sands characterized by a limited suction profile. Notably, the entire range of suction values fell within the 0.01–20 kPa range based on the calibration curves presented by Chandler and ASTM for all the examined sand samples, except sands 9 and 10. Furthermore, the suction values were unobtainable using the two aforementioned calibration curves within the ranges of 0.01–1.47 kPa and 0.01–0.172 kPa. [ABSTRACT FROM AUTHOR]

Polyethylene-, polyvinylidene chloride-, and per- and polyfluoroalkyl substance-coated paper generate microplastics or fluorochemicals in the environment. Here, we report an approach for the development of oil-resistant papers using an environmentally friendly, fluorine-free, water-dispersible poly(dimethylsiloxane) (PDMS) coating on kraft paper. Carboxylic-functionalized PDMS (PDMS-COOH) was synthesized and subsequently neutralized with ammonium bicarbonate to obtain a waterborne emulsion, which was then coated onto kraft paper. The water resistance of the coated paper was determined via Cobb60 measurements. The Cobb60 value was reduced to 2.70 ± 0.14 g/m2 as compared to 87.6 ± 5.1 g/m2 for uncoated paper, suggesting a remarkable improvement in water resistance. Similarly, oil resistance was found to be 12/12 on the kit test scale versus 0/12 for uncoated paper. In addition, the coated paper retained 70–90% of its inherent mechanical properties, and more importantly, the coated paper was recycled via pulp recovery using a standard protocol with a 91.1% yield. [ABSTRACT FROM AUTHOR]

Buckypaper (BP), a flexible and porous material, exhibits photovoltaic properties when exposed to light. In this study, we employed radio frequency (RF) sputtering of zinc oxide (ZnO) followed by rapid thermal annealing to enhance the photovoltaic response of BP. We investigated the impact of various sputtering parameters, such as the gas flow ratio of argon to oxygen and deposition time, on the morphology, composition, resistivity, and photovoltaic characteristics of ZnO-modified BP. Additionally, the photovoltaic performance of the samples under different illumination modes and wavelengths was compared. It was found that optimal sputtering conditions—argon to oxygen flow ratio of 1:2, deposition time of 20 min, and power of 100 watts—resulted in a ZnO film thickness of approximately 45 nanometers. After annealing at 400 °C for 10 min, the ZnO-modified BP demonstrated a significant increase in photocurrent and photovoltage, along with a reduction in resistivity, compared to unmodified BP. Moreover, under gradient illumination, the ZnO-modified BP exhibited a photovoltage enhancement of 14.70-fold and a photocurrent increase of 13.86-fold, compared to uniform illumination. Under blue light, it showed a higher photovoltaic response than under other colors. The enhancement in photovoltaic response is attributed to the formation of a Schottky junction between ZnO and BP, an increased carrier concentration gradient, and an expanded light absorption spectrum. Our results validate that ZnO sputtering followed by annealing is an effective method for modifying BP for photovoltaic applications such as solar cells and photodetectors. [ABSTRACT FROM AUTHOR]

The main part of companies in Bulgaria are built, however in the 70s, and upgraded last decade. The country supplies around 80 % of its supplies of paper, paperboard and pulp with own production. Integrated treatment of wastes is a priority for realizing closed life cycle of materials. The aim of the present work is to investigate the composition and other important characteristics of biomass wood ash wasted from paper industry. The correlations and associations among the chemical characteristics are also studied to find some basic trends and important relationships between two similar wastes from different enterprises. It was proved that all samples taken contained Ba, Cr, Mn, Ni, Co, Al, Fe, Cu and Zn far below the legal limits for such type of products. A product has a certain anti-acidic effect. The other positive result was that the content of iron is between 34 to 60 mg per 1 kg dry waste. The microscopic photos confirmed that the particles are close to the nano-size materials. The content of the elements C, N, H is in good quantities and ratios, which is a prerequisite for their use as a soil improver. By the results of this study, it was confirmed that all samples produced as a result of the thermal treatment and final low water content achieved are free from pathogen microorganisms and different weed seeds, affecting the yield and soil sustainability. That allows determining the optimal ratio between the used components with a view to obtain products with desired thermal stability and physico-chemical properties as soil improvers. [ABSTRACT FROM AUTHOR]

This study focuses on the elimination of residual dyes from industrial wastewater using talc as an adsorbent. Talc is an easily available, ecological, and inexpensive adsorbent. The adsorption process was tested on two model dye samples (Ecozol Blue LR Liquid and Cartasol Yellow 3GF Direct Yellow 132), and two samples of real wastewater from the pulp and paper industry (PM and TP). Kinetic studies revealed that the adsorption of Ecozol Blue LR Liquid followed pseudo-second-order kinetics, while the other tested samples followed pseudo-first-order kinetics. Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherm models were also evaluated. The Langmuir isotherm model best fitted the experimental data for the adsorption of model dye solutions and wastewater sample TP onto talc. For wastewater sample PM, the Dubinin-Radushkevich isotherm model provided the best fit to the experimental data. The results of the adsorption isotherms indicated that the adsorption of all tested systems was favorable and primarily involved physical adsorption. The adsorption efficiency for the model solutions exceeded 90 %. For real wastewater samples, the monitored adsorption efficiency in the COD pollution indicator was less efficient, ranging from 43 to 51 %. The lower efficiency of COD may have resulted from the adsorption of residual dyes with lower specific COD values before the adsorption of other organics. [ABSTRACT FROM AUTHOR]

The pulp and paper industry generates vast quantities of paper sludge, posing significant environmental challenges due to its disposal in landfills or incineration. This study explores the potential of valorizing paper sludge by incorporating it into particleboard production. It aims to optimize sludge content and particle size to enhance board properties—a novel approach to waste management in the wood composites industry. Through systematic variation of sludge content (0–25%) and particle size (< 0.5 to > 2 mm), we assessed the mechanical and physical properties such as internal bond strength (IB), modulus of rupture (MOR), modulus of elasticity (MOE), water absorption (WA), and thickness swelling (TS). The findings indicate that incorporating paper sludge at moderate levels (5–15%) with optimized particle sizes (< 1 mm) significantly improves the mechanical properties of the particleboard, including increased IB, MOR, and MOE while reducing WA and TS. Principal Component Analysis (PCA) further supported these results, revealing that higher-density boards with enhanced mechanical properties absorb less water, highlighting the interrelationship between structural integrity and moisture resistance. The PCA also identified thickness swelling as an independent factor, suggesting that while mechanical properties can be optimized, additional strategies are needed to control swelling. In conclusion, this study demonstrates that up to 15% paper sludge can be effectively used in particleboard production without compromising quality, provided particle size is carefully controlled. This approach not only offers a sustainable solution for managing paper sludge but also contributes to the development of eco-friendly composite materials, aligning with circular economy principles. [ABSTRACT FROM AUTHOR]

In this paper, we developed a paper-based fluorescent sensor using functional composite materials composed of graphene quantum dots (GQDs) coated with molecularly imprinted polymers (MIPs) for the selective detection of tetracycline (TC) in water. GQDs, as eco-friendly fluorophores, were chemically grafted onto the surface of paper fibers. MIPs, serving as the recognition element, were then wrapped around the GQDs via precipitation polymerization using 3-aminopropyltriethoxysilane (APTES) as the functional monomer. Optimal parameters such as quantum dot concentration, grafting time, and elution time were examined to assess the sensor's detection performance. The results revealed that the sensor exhibited a linear response to TC concentrations in the range of 1 to 40 µmol/L, with a limit of detection (LOD) of 0.87 µmol/L. When applied to spiked detection in actual water samples, recoveries ranged from 103.3% to 109.4%. Overall, this paper-based fluorescent sensor (MIPs@GQDs@PAD) shows great potential for portable, multi-channel, and rapid detection of TC in water samples in the future. [ABSTRACT FROM AUTHOR]

The trail making test (TMT) is a commonly used tool for evaluating executive functions, and the activation of cerebral oxygenation in the prefrontal cortex (PFC) during the test can reflect the participation of executive function. This study aimed to compare the differences in cerebral oxygenation in the PFC between the computer- and paper-based versions of the TMT and provide a theoretical basis for the optimization and clinical application of the computer-based version. A total of 32 healthy adult participants completed the computer- and paper-based TMT Types A and B. Cerebral oxygenation changes in the PFC were monitored during the experiment using near-infrared spectroscopy. Moreover, average changes in oxyhemoglobin (Δoxy-Hb) levels at the baseline and during activation periods in different types of testing were compared and analyzed. The number of correct connections in the computer-based version Type B was less than that in the paper-based version Type B (p <.001). The task time of the computer-based version was longer than that of the paper-based version (p <.001). The B/A ratio of the number of correct connections in the computer-based version was lower than that in the paper-based version (p <.001). The Δoxy-Hb in the PFC of the paper-based version was higher than that of the computer-based version (p <.001). Significant differences in oxygenation in the PFC were observed between the paper- and computer-based versions of TMT. After further improvement and correction in the subsequent development of the computer-based TMT, and taking into account the psychological feelings and preferences of the participants when performing different versions of the TMTs, the computer-based TMT is expected to play a good auxiliary role in clinical evaluation. [ABSTRACT FROM AUTHOR]

In this study, a novel, cost-effective, and environmental-friendly acetylcholinesterase (AChE)-based electrochemical biosensor was developed and utilized for paraoxon-ethyl (PE) detection. In this biosensor, cerium oxide (CeO2) and poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PESOT:PSS) modified paper electrode was fabricated by a simple dip-coating method. The synergistic effect of CeO2 and PEDOT:PSS enhance the performance of AChE-based biosensor in terms of sensitivity and selectivity. The electrical conductivity and stability of the fabricated electrode are further improved with the treatment of ethylene glycol (EG). EG decreases the coulombic interactions between PEDOT and PSS molecules, causes polymer chain reorientation, and improves the non-covalent interaction between cellulose molecules and PEDOT, which further leads to higher conductivity. All electrochemical results validate that the biosensor shows good selectivity (Kselectivity < 1), high sensitivity of 52.10 µA/nM, and a low detection limit of 0.12 nM. The accuracy and applicability of the proposed biosensor were also checked with two real samples. All results validate that the fabricated paper electrode can be a promising alternative to other conventional electrodes. [ABSTRACT FROM AUTHOR]

This research investigated the influence of the layered structure of paper on its selected strength properties. Two types of cellulose pulp were used: unbleached kraft pine pulp (UBSK) and unrefined bleached birch kraft pulp (BHK). Multi-ply papers were obtained from layers of appropriate grammage formed separately and bonded in a wet state. Paper layers were formed from primary pulps (UBSK and BHK) or their mixtures (threeply UBSK-BHK paper and three-ply UBSK-BHK-UBSK paper), from which various variants of laboratory paper samples were made. This work focused on three-layer papers. The obtained laboratory sheets were analysed for changes in tear resistance, tensile strength, bursting strength, short span compression strength (SCT), and corrugating medium test (CMT). In most cases, three-layer structures were characterised by higher strength parameters than single-layer papers. The tear strength and SCT of papers consisting of three layers formed from both mixed pulps were slightly lower than those of solid papers. The results demonstrate the feasibility of producing three-ply paper with significantly reduced variability in parameters such as elongation and bursting strength, which are inherently subject to high variability. [ABSTRACT FROM AUTHOR]

In the engine of heavy trucks, the built-in fuel filter assumes the role of "lungs". The core of the filter, namely the fuel filter paper, acts as a filter for small impurities and separates oil and water. In order to be able to separate minute impurities from the fuel, in this study, we prepared a novel fuel oil filter paper with high efficiency and high dust holding capacity based on wet-laid forming by laminating PBT/PP two-component melt-blown nonwoven material and cellulose nanocrystals (CNC)-doped cellulose wood fiber pulp with the fiber mesh combination forming technology. The effects of the CNC mixing ratio, surface density of melt-blown nonwoven material layer, surface density of cellulose wood pulp paper layer and calendaring pressure on the pore size and filtration performance of the composite samples were investigated, and the filtration efficiency of the composite samples on the tiny impurities in the fuel were also studied. The results showed that the novel composite fuel filter paper material prepared by the combined forming technology of fibrous web had high filtration efficiency and dust holding capacity, and the filtration efficiency of the composite samples could respectively reach 99.90% and 99.52% for particles larger than 14 μm and 4 μm in diameter in the fuel. At the same time, the dust holding capacity of the composite sample can reach up to 27.63 mgcm−2. [ABSTRACT FROM AUTHOR]

Enzymes derived from microbial sources have gained increasing popularity in industrial applications over the past decades. Despite the high production cost, alkaline proteases have wide applications in industries such as tanneries, food production, and detergents. In recent years, there has been a shift towards utilizing natural carbon sources for cultivating microorganisms and extracting proteases in order to reduce production costs. This study aimed to investigate the biochemical and kinetic properties of protease enzymes obtained from Aspergillus niger cultivated in a paper waste medium and compare with the enzyme produced in a basal medium. Glucose is a more favorable carbon source compared to cellulose, so paper waste was pretreated with cellulose-degrading bacteria to convert cellulose into smaller carbohydrates. After the growth of A. niger in basal and combinational media, the enzymatic properties were compared between the extracted enzymes by using casein as substrate. The results demonstrated that A. niger could produce protease enzymes in the paper waste medium similar to the basal medium with more than 5-fold cost saving. The specific activity of the enzymes isolated from the basal and paper waste media was calculated to be 184.95 ± 10.56 U ml−1 and 169.88 ± 11.05 U ml−1, respectively. Carbon sources did not affect the optimum pH and temperature of the protease enzyme, which were found to be 8 and 37 °C, respectively. This study provides valuable insights into the production of alkaline protease from A. niger using a combinational medium (paper waste pretreated by cellulose-degrading bacteria), offering a cost-effective approach for industrial applications. [ABSTRACT FROM AUTHOR]

This work demonstrates the application of urea-powered paper-based fuel cells (PFCs) with Hydrogen Peroxide (H2O2) as the oxidant to drive a flexible electronic circuit (ring oscillator (RO)), for the first time. Herein, the electrochemical performance of four different PFCs has been studied by employing non-precious electrodes as the anode and cathode. These are the membraneless PFC with (i) Toray carbon paper (CP) (ii) Nickel (Ni)-mesh (iii) Nickel Cobalt nanoparticles supported on reduced Graphene Oxide loaded on the CP (Ni Co@rGo@CP) and (iv) membrane-based PFC with Ni Co@rGo@CP as the electrodes. In each PFC the same electrode is employed on both the sides. A single membraneless-PFC with Ni-Co@rGo@CP as electrodes delivered a peak power density (Pmax) of 55 µW cm−2, maximum current density (Jmax) of 371 µA cm−2 and an open-circuit voltage (OCV) of 0.7 V at 3 M urea. While, a single membrane-based PFC assembled on an anion exchange membrane with Ni-Co@rGo@CP electrodes, delivered a Pmax of ≈70 µW cm−2 and Jmax of ≈500 µA cm−2 at an OCV of 0.7 V with 3 M urea. Subsequently, a stack of two membrane-based PFCs delivered an OCV of ≈1.4 V for 400 s. Finally, this stack is employed as a power source to drive a RO. The measured frequency and peak-to-peak voltage are 37.52 kHz and 1.04 V, respectively. This demonstration opens a window to implement self-contained flexible electronic system using PFCs as the power source with minimal e-waste. [ABSTRACT FROM AUTHOR]

In most industrialized countries, power transformers built several decades ago are approaching the end of their operational lifespan. The ongoing energy transition, focused on developing 100% renewable energy sources and accelerating global transportation electrification, further exacerbates these assets. Combined with rising electricity demand, there is an increasing risk of critical transformers' degradation acceleration. In this context, understanding the aging mechanisms of the insulation system inside these essential assets, which form the core of every energy network, becomes paramount for today's managers and engineers responsible for their operations. The acids generated through oil oxidation can be classified into two categories: low molecular weight acids (LMAs), which are inherently more hydrophilic and consequently have a greater impact on the degradation rate of solid insulation through hydrolysis, and high molecular weight acids (HMAs), which do not significantly contribute to the degradation of paper insulation. This study specifically addresses the impact of acids generated through oil oxidation—focusing on LMAs. New oil samples were infused with different ratios of LMAs before impregnation. The impregnated paper samples underwent thermal aging at 115 °C. Different physicochemical and dielectric properties were investigated. The investigations revealed that oils blended with formic acid exhibited more adverse effects on the insulation system compared to other LMAs. This information is essential for industry professionals seeking to mitigate the risks associated with transformer degradation and extend the lifespan of these critical assets during the energy transition. [ABSTRACT FROM AUTHOR]

Compared to traditional lithium metal batteries, anode-free lithium metal batteries use bare current collectors as an anode instead of Li metal, making them highly promising for mass production and achieving high-energy density. The current collector, as the sole component of the anode, is crucial in lithium deposition-stripping behavior and greatly impacts the rate of Li depletion from the cathode. In this study, to investigate the lithiophilicity effect of the current collector on the solid electrolyte interface (SEI) film construction and cycling performance of anode-free lithium batteries, various lightweight paper-based current collectors were prepared by electroless plating Cu and lipophilic Ag on low-dust paper (LDP). The areal densities of the as-prepared LDP@Cu, LDP@Cu-Ag, and LDP@Ag were approximately 0.33 mg cm−2. The use of lipophilic Ag-coated collectors with varying loadings allowed for the regulation of lipophilicity. The impacts of these collectors on the distribution of SEI components and Li depletion rate in common electrolytes were investigated. The findings suggest that higher loadings of lipophilic materials, such as Ag, on the current collector increase its lipophilicity but also lead to significant Li depletion during the cycling process in full-cell anode-free Li metal batteries. Thus, moderately lithiophilic current collectors, such as LDP@Cu-Ag, show more potential for Li deposition and striping and stable SEI with a low speed of Li depletion. [ABSTRACT FROM AUTHOR]

Vibration sensors are widely used in many fields like industry, agriculture, military, medicine, environment, etc. However, due to the speedy upgrading, most sensors composed of rigid or even toxic materials cause pollution to the environment and give rise to an increased amount of electronic waste. To meet the requirement of green electronics, biodegradable materials are advocated to be used to develop vibration sensors. Herein, a vibration sensor is reported based on a strategy of pencil-drawing graphite on paper. Specifically, a repeated pencil-drawing process is carried out on paper with a zigzag-shaped framework and parallel microgrooves, to form a graphite coating, thus serving as a functional conductive layer for electromechanical signal conversion. To enhance the sensor's sensitivity to vibration, a mass is loaded in the center of the paper, so that higher oscillation amplitude could happen under vibrational excitation. In so doing, the paper-based sensor can respond to vibrations with a wide frequency range from 5 Hz to 1 kHz, and vibrations with a maximum acceleration of 10 g. The results demonstrate that the sensor can not only be utilized for monitoring vibrations generated by the knuckle-knocking of plastic plates or objects falling down but also can be used to detect vibration in areas such as the shield cut head to assess the working conditions of machinery. The paper-based MEMS vibration sensor exhibits merits like easy fabrication, low cost, and being environmentally friendly, which indicates its great application potential in vibration monitoring fields. [ABSTRACT FROM AUTHOR]

Paper relics, as carrieres of historical civilization's records and inheritance, could be severely acidic and brittle over time. In this study, the multi-functional dispersion of nanometer magnesium oxide (MgO) carried by 3-aminopropyl triethoxysilane-modified bacterial cellulose (KH550-BC) was applied in the impregnation process to repair aged paper, aiming at solving the key problems of anti-acid and strength recovery in the protection of ancient books. The KH550-BC/MgO treatment demonstrated enhanced functional efficacy in repairing aged paper, attributed to the homogeneous and stable distribution of MgO within the nanofibers of BC networks, with minimal impact on the paper's wettability and color. Furthermore, the treatment facilitated the formation of adequate alkali reserves and hydrogen bonding, resulting in superior anti-aging properties in the treated paper during prolonged preservation. Even after 30 days of hygrothermal aging tests, the paper repaired by KH550-BC/MgO was still in a gently alkaline environment (pH was about 7.56), alongside a 32.18% elevation compared to the untreated paper regarding the tear index. The results of this work indicate that KH550-BC/MgO is an effective reinforcement material for improving the long-term restoration of ancient books. [ABSTRACT FROM AUTHOR]

In order to reveal the migration and evolution of gas molecules in the actual oil–paper insulation composite system of transformer from the molecular level, the diffusion behavior of seven gas molecules (H2, CO, CO2, CH4, C2H2, C2H4, C2H6) generated during the operation and aging of oil-immersed transformers in the oil–paper composite insulation system is studied by molecular dynamics. Firstly, based on the molecular dynamics software, the model of the oil–paper composite insulation system and the gas molecule model is constructed. In order to compare and analyze the diffusion properties of gas molecules in a single medium, a single model of insulating oil and cellulose is also constructed. Then, the diffusion coefficients of gas molecules in the insulating oil, cellulose, and oil–paper insulating composite system are simulated and calculated. And the differences in the diffusion properties of gas molecules in the three insulating mediums are discussed. Finally, the microscopic mechanism of diffusion of different gas molecules in the three mediums is analyzed. The simulation results show that among the three mediums, the diffusion coefficient of H2 is the largest, while the diffusion coefficients of the other gas molecules are not very different. The diffusion coefficients of the seven gas molecules are the smallest in the oil-immersed paper composite insulation system, followed by cellulose, while the diffusion coefficients are the largest in mineral oil. It indicates that the diffusion of gas molecules is inhibited in oil–paper insulation systems where the insulating paper is completely immersed in oil. This is mainly due to the fact that the insulating oil completely penetrates into the paper, filling the pores and voids between the fibers, resulting in a reduction in the transition vacancies of the intermediate gas molecules, which hinders the diffusion of the gas molecules. [ABSTRACT FROM AUTHOR]

In this study, a comparative analysis of silver nanoparticles treatment and chitosan coating on packaging paper barrier properties was carried out. In order to examine the water, grease, and antibacterial barrier properties of silver nanoparticle-treated and chitosan-coated laboratory-obtained paper samples, a mixture of bleached softwood and hardwood celluloses was used. In order to conduct the comparative analysis SEM, water contact angle, Cobb60, and Kit tests were carried out on a cellulose sample, and four paper samples (three of them treated with silver nanoparticles—1, 2, and 3 mL/20 cm2 or chitosan coated—0.5, 1, and 2 g/m2) together with the inhibition activity against nine Gram-positive and Gram-negative bacteria, yeast, and fungal strains. The study found out that increasing the silver nanoparticle treatment and chitosan coating led to improved water resistance, while grease resistance was improved only for chitosan coated paper samples. Additionally, paper treated with 3 mL/20 cm2 of silver nanoparticles had the highest antibacterial protection (81.6%) against the Gram-positive bacterium Staphylococcus aureus, followed by Gram-negative Escherichia coli (75.8%). For the rest of the studied microorganisms, the average efficiency of the treated paper was 40.79%. The treatment of the paper with 1 and 2 mL/20 cm2 of silver nanoparticles was less effective—27.13 and 39.83%, respectively. The antibacterial protection of 2 g/m2 chitosan-coated paper samples was the most effective (average 79%) against the tested bacterial, yeast, and fungal strains. At 1 and 0.5 g/m2 chitosan coatings, the efficiency was 72.38% and 54.67%, respectively. Gram-positive bacteria, yeasts, and fungal strains were more sensitive to chitosan supplementation. [ABSTRACT FROM AUTHOR]

In the era of liquid biopsy, microRNAs emerge as promising candidates for the early diagnosis and prognosis of cancer, offering valuable insights into the disease's development. Among all the existing analytical approaches, even if traditional approaches such as the nucleic acid amplification ones have the advantages to be highly sensitive, they cannot be used at the point-of-care, while sensors might be poorly sensitive despite their portability. In order to improve the analytical performance of existing electroanalytical systems, we demonstrate how a simple chromatographic paper-based disk might be useful to rationally improve the sensitivity, depending on the number of preconcentration cycles. A paper-based electrochemical platform for miRNA detection has been developed by modifying a paper-based electrode with a methylene blue (MB)-modified single-stranded sequence (ssDNA) complementary to the chosen miRNA, namely miR-224 that is associated with lung cancer. A detection limit of ca. 0.6 nM has been obtained in spiked human serum samples. To further enhance the sensitivity, an external chromatographic wax-patterned paper-based disk has been adopted to preconcentrate the sample, and this has been demonstrated both in standard and in serum solutions. For each solution, three miR-224 levels have been preconcentrated, obtaining a satisfactory lowering detection limit of ca. 50 pM using a simple and sustainable procedure. This approach opens wide possibilities in the field of analytical and bioanalytical chemistry, being useful not only for electrochemistry but also for other architectures of detection and transduction. [ABSTRACT FROM AUTHOR]

In the field of book heritage, it is important to develop cleaning/disinfecting treatments that can slow down the degradation of paper to prevent evident and irreversible damage. The objectives of the cleaning treatments are to remove external contaminants and oxidation and decomposition products of the paper, but these processes must not modify the unique characteristics of the book heritage resulting in irreversible changes in the structure of the paper. Recently, several innovative cleaning treatments were developed with the aim of being minimally invasive; however, to assess the effect of these treatments on paper, it is necessary to use a diagnostic non-destructive, rapid, and affordable process. In previous work, we used surface scanning Raman spectroscopy to develop a diagnostic protocol able to follow the aging processes of the paper, discriminating between hydrolysis and oxidation. In this paper, we applied this protocol to study the action of different types of treatments (hydrogel and EUV irradiation), evaluating both their effectiveness and impact on paper parameters. The results reported here demonstrate that the developed in operando diagnostic procedure can follow the changes in the paper structure comparing them to the variability due to the intrinsic inhomogeneity of paper, without sample contact in a rapid and effective way. [ABSTRACT FROM AUTHOR]

A smooth and dense surface of the base paper is advantageous when the goal is to apply a liquid coating as a barrier layer. For such a base paper, non-wood fibers derived from wheat straw could be an alternative to wood fibers. In this research paper, wheat straw pulp was refined with different beating levels (up to 600 revolutions) followed by different calendering pressure loads (up to 50 N/mm) to test its influence on mechanical and surface properties. Alkyl ketene dimer (AKD) was used as sizing agent with concentrations up to 0.2 wt% followed by a mineral-based precoating to test its influence on the smoothness. Eucalyptus pulp was chosen as a benchmark. After beating, the initial Schopper-Riegler degrees of 28 °SR increased to 56 °SR. Beating also increased the tensile index from 24 to 49 Nm/g, the burst index from 1.2 to 2.8 kPa·m²/g, and the tear index decreased from 3.3 to 2.8 mN·m²/g. Calendering reduced the initial roughness of 370 mL/min to 30 mL/min. When precoated and calendered again, the value was lowered to 15 mL/min. In summary, wheat straw paper is a relevant alternative to wood-derived base paper to produce barrier papers. Compared to eucalyptus, wheat straw paper showed better smoothness and much lower air permeability indicating excellent suitability for barrier coating. [ABSTRACT FROM AUTHOR]