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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]

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]

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]

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]

Developing cost-effective and stable materials for the electrocatalysis of hydrogen evolution reaction (HER) remains challenging. In this study, efficient catalysts for HER were synthesized by integrating the cobalt and molybdenum oxides via electrodeposition, followed by subsequent sulfurization of the as-prepared oxides using chemical vapor deposition (CVD). This methodology allowed the incorporation of both cobalt and molybdenum components into the catalyst in a single step. The as-synthesized CoSx@MoSx/MoOx-based catalysts exhibited excellent hydrogen production performance in acidic media owing to the presence of Co-S and Mo-S bonds in the hybrid structure. Particularly, CoSx@MoSx/MoOx(90@360) and MoSx@CoOx(180@180) displayed the best HER performances with low overpotentials of 80 mV and 150 mV, respectively. The catalysts were highly stable, with their stability preserved for over 1000 cycles with marginal reduction in overall efficiency. Therefore, these findings suggest the potential of CoSx@MoSx/MoOx and MoSx@CoOx composites as ideal candidates for developing low-cost catalysts for electrochemical hydrogen production. [ABSTRACT FROM AUTHOR]

Carbon paper is one of the most widely used gas diffusion layer substrate materials due to its stable performance, relatively low cost, and easy for subsequent processing. Water-soluble phenolic resin, which is more ecologically friendly than alcohol-soluble phenolic resin, was used to prepare carbon paper as the precursor of the carbon matrix. And the effect of different resin solution concentrations on the properties of carbon paper was explored. The results showed that the graphitization, electrical conductivity and mechanical properties of carbon paper increased with the increase of resin solution concentration. When the concentration of resin solution was 20 wt%, the performance of carbon paper was relatively optimal. The graphitization of the carbon paper reached 65.45%, the porosity reached 80.74%, the resistance value at 1 MPa pressure was only 7.61 mΩ cm2, the tensile strength was 1.57 MPa, and the elastic modulus was 1210.98 MPa. [ABSTRACT FROM AUTHOR]

Size presses on paper machines are used to apply a solution of a polymer - usually starch - to the surface of the sheet and thereby to increase the stiffness, surface strength, and printing quality of the product. This article reviews publications dealing with the size press equipment, the materials, and factors affecting both the operating efficiency and attributes of the resulting paper. The emergence of film-press equipment (e.g. blademetering size presses) in the 1980s has greatly decreased the frequency of web breaks and increased productivity. Starch technology at the size press, though relatively mature, continues to evolve. By adjustment of starch attributes, solids levels, and incorporating other additives, modern papermakers can tune size press outcomes to meet a range of paper product requirements, including strength, hydrophobicity, and the reduction of air permeability. By application of various synthetic polymers, mineral particles, and even nanocellulose in combination with starch or other base polymers, there is potential to extend the technology to meet a range of future needs for paper products. [ABSTRACT FROM AUTHOR]

The pulp and paper industry is critical to global industrial and economic development. Recently, India's pulp and paper industries have been facing severe competitive challenges. The challenges have impaired the environmental performance and resulted in the closure of several operations. Assessment and prediction of the performance of the Indian pulp and paper industry using various parameters is a critical task for researchers. This study proposes a framework for performance assessment and prediction based on Data Envelopment Analysis (DEA), Artificial Neural Networks, and Deep Learning (DL) to assist industry administration and decision-making. We presented a case study based on eight industries to demonstrate the methodology's applicability. This study analyses and predicts industry performance based on sample data observations over 30 years. The result suggests the DEA-DL-based efficiency prediction has an overall MSE of 0.08 compared with the actual efficiency. Furthermore, the efficiency rankings are compared between the three techniques. The results suggest that the integrated DEA-DL method is primarily accurate in most scenarios with the actual values. The findings of this study provide a comprehensive analysis of environmental performance for policymakers. [ABSTRACT FROM AUTHOR]

Achieving the desired properties of paper such as strength, durability, and printability remains challenging. Paper mills employ calcium carbonate (CaCO3) as a filler to boost paper's brightness, opacity, and printability. However, weak interaction between cellulose fibers and CaCO3 particles creates different issues in the papermaking industry. Therefore, this study explores the influence of various inorganic additives as crosslinkers such as mesoporous SiO2 nanospheres, TiO2 nanoparticles, h-BN nanoflakes, and hydroxylated h-BN nanoflakes (h-BN-OH) on inorganic fillers content in the paper. They were introduced to the paper pulp in the form of a polyethylene glycol (PEG) suspension to enable bonding between the inorganic particles and the paper pulp. Our findings have been revealed based on detailed microscopic and structural analyses, e.g., transmission and scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and N2 adsorption/desorption isotherms. Finally, the inorganic fillers (CaCO3 and respective inorganic additives) content was evaluated following ISO 1762:2001 guidelines. Conducted evaluations allowed us to identify the most efficient crosslinker (SiO2 nanoparticles) in terms of inorganic filler retention. Paper sheets modified with SiO2 enhance the retention of the fillers by ~12.1%. Therefore, we believe these findings offer valuable insights for enhancing the papermaking process toward boosting the quality of the resulting paper. [ABSTRACT FROM AUTHOR]