Search

This article presents the information on the valorization of waste generated during the production of tissue paper. The possibility of bioconversion of the polysaccharide part of paper sludge into simple sugars has been evaluated. The options for processing the paper sludge before enzymic hydrolysis to achieve the maximum yield of monosaccharides have been considered. Pretreatment with acids has been found to be a key step before the biocatalytic cleavage of waste polysaccharides. An additional yield of enzymic hydrolysis products after pretreatment with acids has been obtained by pre-extraction of the paper sludge with spirit or acetone. It has been established that the most intense enzymic hydrolysis of readily available fractions of the paper sludge takes place in the first 10–12 hours. Further, the process slows down, probably due to the action of the remaining components of the fillers, as well as an increase in the proportion of the difficult-to-hydrolyze polysaccharide part. In all cases, the proportion of absolutely dry non-hydrolyzed residue has been about 43±2 % of the dry matter of the paper sludge. The main products of enzymic hydrolysis have been glucose and xylose. The resulting sugars have been used for mixotrophic cultivation of the Tetradesmus obliquus and Chlorella vulgaris algae. Yeast strains have been selected for the conversion of monosaccharides from the paper sludge. In a series of experiments on non-sterile yeast cultivation, the Candida utilis PAL D and Debaryomyces hansenii SWING R cultures have turned out to be the most productive (within 2.10±0.14 g of air-dry yeast weight/dm3 per 24 hours). The degree of conversion of hydrolysate sugars has been 70±2 %. Most of the remaining sugars (about 80 %) have been represented by xylose. Complete utilization of the sugars has taken place on the 2nd day when having added an extra nitrogen source to the medium. On the other hand, the spent nutrient medium after yeast separation has been suitable for mixotrophic cultivation of microalgae. It has been revealed that the economic costs of pre-treatment of the paper sludge with nitric acid can be leveled by using the resulting salts as a nitrogen source for cultivating yeast. In doing so, the yield of yeast biomass increases by almost 2 times.

This research was designed to assess the yield and quality of ash prepared from different types of waste papers. Waste newspapers, writing papers, and cartons were selected for combustion to obtain the ashes and coded as WNPA, WWPA, and WCPA, respectively. The waste papers were incinerated simultaneously in separate but identical incinerators at 850 ℃. An experiment on the yield of the ashes was performed on two days before the ashes obtained were mixed based on the type of waste papers from which they were derived. The results showed that irrespective of the day and time, the WCPA was the most yielded (14.1%), followed by the WWPA (12.3%), and then the WNPA (11.9%). Also, it was found that all the ashes possessed flow properties acceptable for engineering applications. However, the WCPA would ensure the best performance if applied, especially as a partial replacement material for cement. While the WWPA was found to be richer than the WNPA, the WCPA was the richest in terms of the proportions of key oxides for strength development. In general, the percentages of various chemical components of each ash complied with the standard specifications for cement except in the case of losses on ignition of the WNPA and WWPA, which were about 0.53% and 0.02%, respectively, beyond the maximum stipulated value.

Abstract To compare the urine Congo‐red dot paper test (CRD) with dipstick urinalysis to screen preeclampsia (PE). A total of 409 paired spot urine samples were obtained prospectively from women with suspected pre‐eclampsia attending for routine hospital visits. Congo‐red dot paper test and dipstick urinalysis were examined and compared to screen pre‐eclampsia. The agreement between the two urinary test is modest (kappa coefficient = 0.28, 95% CI 0.14–0.42). The specificity of CRD was higher than urinalysis (97.4% vs. 90.4%, p

Contemporary ESL education focuses on screen-based reading, specifically in the context of university level learners. Also, a sudden shift from paper bound reading activities to screen-based tasks was inevitable in response to COVID-19 outbreak. In this regard, the case of inferential and advanced level reading among the young ESL learners of developing countries appears researchable because of the general low digital literacy of these learners. This study, therefore, aimed to investigate the effect of reading mode shift from paper to screen on the inferential comprehension performance among Pakistani ESL learners at university level. A total of 426 undergraduate learners were sampled from Bachelor of Science program in a well-known university in the city of Lahore, Pakistan. Inferential reading was conceptualized through Bloom’s higher order thinking skills, that is, Analyzing, Evaluating and Creating skills therefore the reading comprehension test was based on these skills. Adopting sequential test administration, first the paper-based reading test, and later the screen-based reading was given. The obtained data were analyzed using Rendell’s XCALIBRE and SPSS V. 26.0. The logit scale descriptives, learner ability (θ), and mean scores demonstrated that the learners performed significantly higher in the paper test as compared to screen test. Moreover, it was found that the effect of reading mode shift was larger in Creating skill. The findings may have significant implications for reading mode selection, enhancement of digital competence and effect of reading mode shift in developing countries with inadequate IT facilitation and digital literacy among ESL learners.

The present study was conducted to draw the co-authorship network of hot papers of science citation index in the Web of Science (WOS) database from 2020 to 2021. This investigation is a descriptive study using a scientometrics approach. This research was conducted using social network analysis indices to visualize the co-authorship networks of hot papers in the science citation index. The structure of the co-authorship network of researchers of hot papers in the field of science consists of 47,045 authors who have contributed to the publication of 3475 hot papers from 2020 to 2021, which indicates the high co-authorship of these authors. Moreover, it was found that among the co-authorship patterns of these researchers, the most significant number of articles during the studied years was related to the five-author collaborations. Moreover, the average Collaboration Coefficient (CC) of the authors of hot papers was higher than 0.80, indicating the authors' strong tendency to produce joint articles. The high collaboration of the authors of hot papers in the science citation index can be one of the reasons for increasing the level of visibility and the potential for using them.

Reliable data on U.S. paper and cardboard waste by location and type are critical for developing waste-reduction solutions, but detailed geographic analysis is lacking in the literature. In this study, we employ statistical and geospatial methods to assess paper and cardboard waste in the United States by type at the national, state, county, and local levels. Of the estimated 110 million tons of paper and cardboard waste managed domestically in 2019, approximately 56% was landfilled, 6% was combusted, and 38% was recycled. The estimated market value of paper and cardboard lost to landfilling in 2019 was $4 billion, and the estimated losses of embodied energy and combustion energy were equivalent to 9% and 4% of U.S. primary industrial energy consumption, respectively. Associated landfilling fees amounted to almost $4 billion. This study aims to inform efforts to implement beneficial waste-management strategies by policy makers, researchers, businesses, and communities across the United States and to provide a model for similar studies in other parts of the world.

Introduction: Monitoring the atypical antipsychotic drug clozapine is crucial to ensure patient safety. This article showcases a high-throughput analytical method for measuring clozapine and its primary metabolite norclozapine (N-desmethylclozapine) in serum using paper spray mass spectrometry (PS-MS). Objectives: This study aimed to assess the viability of a PS-MS method for the rapid measurement of clozapine and norclozapine in human serum samples as an alternative to liquid chromatography mass spectrometry (LC-MS). Methods: Serum samples were processed by protein precipitation followed by deposition of the supernatant containing labelled internal standards onto paper spray substrates mounted in cartridges. Analytes were then analyzed using a triple quadrupole mass spectrometer equipped with a commercial paper spray ionization source. The results obtained from the patient samples were compared to those from a validated LC-MS assay. Results: PS-MS calibrations for clozapine and norclozapine were linear (R2 > 0.99) over five days. Between-run precision was below 8 %, and within-run precision did not exceed 10 %. When compared to a validated LC-MS method, the mean bias for 39 patient samples was −9% for clozapine and −1% for norclozapine, with no outliers. Mass spectrometry ion ratio comparisons indicated no interference for patient samples above the lower limit of quantification. There was less than 7 % change in the measured concentrations of both analytes over five days for samples dried on paper substrates. Notably, virtually no maintenance of the MS source was required during this study. Conclusion: This study illustrates the potential of PS-MS for serum drug monitoring in the clinical laboratory.

Besides scientific impact, papers can also achieve a technological impact that remains less known in the scientific community. Cited papers in the patents are considered as the index to measure the technological impact. This study aimed to analyze the technological impact of Iranian publications using co-authorship and co-word map, their evolution, the journals, and the subject areas of these publications. This applied research focuses on the quantitative study and visualization with a scientometric approach. The research population was all studies (4554 records) that were published during 2011-2020 in one of the Iranian institutions and had been cited by one of the international patents. The data collection tool was the SciVal database. CiteSpace and Excel spreadsheets were used to analyze the data. Of the 4,554 papers cited by the scholarly outputs that have been cited in patents e patents, most of them were published in collaboration with the USA (9%). Islamic Azad University and Tehran University of Medical Sciences (13% each) were the most active Iranian universities. The number of Iranian papers cited in patents had a downward trend from 686 in 2011 to 57 in 2020. RSC Advances journal was the first top journal to publish these papers. Of 27 subject areas, engineering (24.1%) was the first popular subject that patents cite in their publications. The cluster analysis of keywords identified 8 clusters, including “x-ray diffraction,” “animal,” “adult,” “escherichia coli,” “tissue engineering,” “coronavirus infection,” “neural network,” and “methane.” The technological impact of Iranian research has declined in recent years. It is suggested that research policymakers should consider scholarly outputs that have been cited in patents, which, in a way, shows the flow of knowledge to the industry and encourages researchers to produce such papers.

Abstract Soot stain from diverse sources is the most common stain that stains historical paper documents found in libraries, museums, and storage facilities. It is believed to be one of the types of deterioration that arises from the contact between stains and paper sheets. Therefore, in the present work, the effectiveness of the synthesized hybrid nanogel consisting of carbopol and nanoparticles (NPs) of ZnO, TiO2, or Fe3O4, in low and high-viscosity forms, for eliminating soot stains from historical paper manuscripts was conducted. The prepared hybrid nanogels were characterized utilizing the TEM, AFM, XRD, DLS, and Zeta Potential techniques. Following preparation, the soot-stained paper samples were heated to 105 °C for 6 days, a process known as accelerated thermal aging. Surface morphology, mechanical properties and the color change of the paper samples were investigated. The prepared hybrid nanogel had a spherical shape with well-defined edges and uniform size, with an average particle diameter ranging from 30 to 35 nm. There was no significant NPs agglomeration seen, suggesting uniform dispersion in the carbopol matrix. Additionally, the prepared gels' crystal structure and phase purity were revealed by the XRD analysis results. Paper fibers were visible in some parts of the treated sample with TiO2/carbopol hybrid nanogel at high-viscosity before aging. Cleaning soot-stained paper samples using high-viscosity Fe3O4/carbopol hybrid nanogel is more successful than using low-viscosity nanogel. the sample treated with high-viscosity ZnONPs/carbopol hybrid nanogel produced the highest total color differences (ΔE) (26.17). The paper sample treated with high-viscosity ZnO/carbopol hybrid nanogel exhibited the maximum tensile strength (61.8 N/mm2) and elongation at break (1.174%). The evaluation of the paper samples both before and after the cleaning process revealed that, the treatment with high-viscosity ZnO/carbopol hybrid nanogel gave the best results in removing soot stains from stained paper samples.

To improve the surface properties of low-density wood, poplar wood was functionalized by laminating Al2O3 impregnated paper onto poplar wood (Populus tomentosa Carr.) via unilateral surface compression. Bonding strength between Al2O3 impregnated paper and wood reached up to 3.08 MPa, meeting commercial grade I requirements for impregnated paper laminated wood flooring. A cross-linked structure between Al2O3 impregnated paper and wood was formed without visible cracks or other defects. Density of the functionalized wood surface increased remarkably and the surface hardness was significantly improved, surpassing that of hardwoods for wood flooring. The functionalized wood surface also exhibited high wear resistance, which reached to the specification for commercial grade I impregnated paper laminated wood flooring. Additionally, the water resistance of the functionalized wood surface was significantly improved through lamination with Al2O3 impregnated paper. The functionalized wood demonstrated high applicability for wood flooring.

Microbially contaminated food can cause serious health hazards and economic losses, therefore sensitive, rapid, and highly specific visual detection is called for. Traditional detection of microorganisms is complex and time-consuming, which cannot meet current testing demands. The emergence of paper-based biosensors provided an effective method for efficient and visual detection of microorganisms, due to its high speed, all-in-one device, low cost, and convenience. This review focused on 5 biomarkers, namely nucleic acids, proteins, lipopolysaccharides, metabolites, and the whole microorganism of microorganisms. Besides, the recognition methods were summed up in 5 forms, including immunological recognition, aptamer recognition, nucleic acid amplification-mediated recognition, DNAzyme recognition and clustered regularly interspaced short palindromic repeats mediated recognition. In addition, we summarized the applications of paper-based biosensors in the detection of microorganisms thoroughly. Through the exploration of different biomarkers, identification methods, and applications, we hope to provide a reference for the development of paper-based biosensors and their application in safeguarding the food chain.

Se describen a los micro-papers como formatos novedosos e incipientes para la difusión del conocimiento científico, tanto en revistas científicas como a través de otros métodos nativos del Internet (repositorios, blogs, etcétera). Planteamos la importancia de la utilización de este formato reducido de comunicación de la ciencia para transmitir ciertos tipos de hallazgos, pues presenta una condensación de la información básica en un documento breve, de fácil lectura y con amplia audiencia, sin perder la calidad propia de los trabajos científicos revisados. Para ello, se realiza un estudio descriptivo de carácter exploratorio por medio de una revisión bibliográfica que ahonda en su uso actual y experiencias previas. Concluimos que su viabilidad para la difusión de contenidos científicos concretos busca la agilidad, sin que ello implique la pérdida de la calidad en la difusión científica.

Nanofibrillated cellulose (NFC) and its combined usage with cationic starch and a cationic copolymer of acrylamide were studied in relation to the properties of paper. Independent pulp treatments using additives separately included 0%, 5%, 10%, and 15% refined long fiber pulp, 3 and 6% NFC, 0.75 and 1.5% cationic starch and 0.07% and 0.15% cationic polyacrylamide and combined treatments. Handsheets were made of the above treatments, and finally their optical and microscopic properties were evaluated. Increasing the NFC content to 6% increased the brightness and yellowness of the white liner by 13% and 21%, respectively. The liner opacity was also reduced by 1%. Additionally, increasing NFC by 6% compared to imported long fibers, the brightness and yellowness of the white liner increased 5.44% and 6.3%, respectively. The liner opacity was also reduced by 1%. A 1.5% cationic starch addition to NFC increased the brightness of the white liner by 4.4%, its whiteness increased 1.5%, and its yellowness increased 2.1%. The opacity of the liner was also reduced by 7.1%. The use of NFC and cationic starch can improve the optical properties of the white liner, while imported long fibers may be problematic.

Abstract Gels prepared from the polysaccharide gellan are used for aqueous poulticing treatments in paper conservation when the application of water must be restricted. Optimal use of the rigid, yet shapeable gel requires direct contact with the paper surface, which carries the risk of gel residues on the treated surface. We used acid methanolysis as a destructive analytical method to detect rhamnose as a component of gellan, which was undetectable with ATR-FTIR spectroscopy. We show that there is a significant probability of leaving gellan residues on the paper. Conservators should be aware of this potential side effect when considering the use of gellan poultices in direct contact with paper objects.

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. blade-metering 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.

In the field of paper conservation and archival research, identifying the raw materials of paper is important to elucidate its history and culture. As the most basic element of the raw materials for paper, fibers have not been sufficiently investigated. In this study, we propose a nondestructive method for estimating paper fibers from macro photographs ( $4000\times3000$ pixels) captured using a digital camera. The proposed method consists of background patch (500 pixels per side) detection (BPD), wherein background regions with no text are identified; patch fiber classification (PFC), wherein background patches obtained after BPD are analyzed for fiber classification; and paper fiber estimation (PFE), wherein macro images obtained after PFC are analyzed for fiber estimation. BPD and PFC are employed to perform patch-based classification on segmented macro images, which are reconstructed during PFE to obtain the final fiber estimation results. We performed experiments using 1337 macro images (64176 patches) to evaluate the fiber estimation accuracy for kozo, mitsumata, and gampi via three-fold cross-validation. The average fiber classification accuracy for patch images was observed to be 79.1%; accordingly, the average fiber estimation accuracy for macro images was 85.8%. Experimental results indicated that PFE can be realized in a nondestructive manner on macro images of paper captured using a digital camera.

Impinging air jets can be used to dewater, heat, and dry the web of tissue paper. High velocities of the air jets degrade the paper, and appropriate adjustments to the jet velocity and the distance of the nozzle from the surface of the wet web are crucial to obtain the highest quality product. This work investigated the correlation between the velocity of the air jet and the strength of paper subjected to the impingement method. Papers with an initial moisture content of 20% and various pulp mixes were tested, and the physical properties of papers were explored. After impinging an air jet, different tensile strength limits were obtained in the machine and cross directions. The paper had lower apparent density and higher roughness compared to classical pressing. The dependence of tensile strength and roughness on the fibers composition also was determined. Increasing the amount of eucalyptus fibers in impingement dewatered paper resulted in a decrease in its tensile strength and roughness. The value of elongation before breaking was the highest for softwood papers after the impingement method. The maximum velocity of an air jet that can be used to dewater or dry paper without the risk of damage to the papers was determined.

Abstract Numerous natural dyes were used to dye mediaeval Islamic paper from the tenth to the nineteenth century, using a variety of techniques. The objective of this research is to develop an analytical method using high performance liquid chromatography with diode array detection (HPLC–DAD) to identify natural dyes in forty historical Islamic paper manuscripts from two collections. In addition, novel information was obtained from original treatises containing recipes for dyeing paper and the chronological use of dyes in dyeing mediaeval Islamic paper between the tenth and seventeenth centuries. The results show that thirty-four of the forty manuscripts examined contained dyes. Six natural dyes were detected, including henna, madder, lac, safflower, turmeric, and weld. This is the first study aimed at developing a method for determining various natural dyes in Islamic paper from a wide historical and geographical range in the mediaeval time and to fill significant gaps in the technical and historical knowledge of papermaking.

Industrial production and domestic discharge produce a large amount of oily wastewater, which seriously affects the stability of the ecological environment. Membrane separation technology provides another path to treating oily wastewater. And appropriate surface modification of the membrane helps to achieve high efficiency of treating oily wastewater. With green, economy and stability been more concerned. The focal research reports a completely biodegradable all cellulose composite filter paper (ACCFP) composed of I-cellulose macrofibers and II-cellulose matrix. It is a simple one-step impregnation method to adjust the surface microstructure of the pristine filter paper (PFP), and it does not involve with chemical reaction. The pre-wetted ACCFP consist of II-cellulose hydrogel and I-cellulose reinforcement in the process of oil-water separation. This layer of hydrogel is the fundamental to underwater superoleophobicity, which determines their eligibility for applications of efficient oil-water mixture or oil-in-water (oil/water) emulsion separation. The separation efficiency of oil-water mixture and oil/water emulsion exceed 95% and 99.9%, respectively. In addition, excellent mechanical properties of ACCFP in dry and wet conditions ensure its stability in service and prolong service life in applications. The focal study provides a new method for high-performance oil-water separation and it is more in line with sustainable chemistry.

Carbon fibre-reinforced ultra-high temperature ceramics (UHTCs) are considered a class of promising materials for several applications, the most appealing ones being in the aerospace sector. Reinforcement is necessary to overcome the brittleness and low thermal shock resistance of ceramics and is often provided through the addition of carbon fibres or other carbon-based phases, such as nanotubes, graphene, and graphite. The present work is focused on the toughening of UHTCs through incorporation of 30−50 vol% thin, ordered graphite layers from conventional filter paper followed by hot pressing sintering. Cellulose filter paper was selected because it undergoes thermolysis with no melting stage forming a strong carbonaceous residue that can be used as toughener. Microstructure and mechanical properties of toughened composites were compared to those of other materials reinforced with short carbon fibres and the effect of different distribution of graphite was studied. Addition of graphite allowed toughness to be increased from 3−4 MPa·m1/2 (for un-reinforced materials) to 5.1−5.5 MPa·m1/2, similar to results obtained with short fibre reinforcement. The high-temperature properties, such as strength and toughness as well as oxidation resistance at 1500 ℃, were also examined.

Paper pulp is a lignocellulosic fibrous material used in the industrial production of paper and board products. In addition to cellulose and hemicellulose, paper pulp contains 1 to 20% lignin, depending on the raw materials and pulping process used. Lignin is a heterogenous aromatic polymer that is hydrophobic and more resistant to microbial degradation compared to the easily biodegradable cellulose and hemicellulose. In this study, the biodegradation of paper pulps containing varying amounts of lignin was examined in soil and marine environments using ISO testing methods. Lignin significantly reduced the mineralization of paper pulps to CO2 in both environmental conditions, and a strong inverse correlation between lignin content and the mineralization to CO2 was observed. A similar impact was observed with natural materials containing lignin, such as birch sawdust. Since the calculation of biodegradability in most ISO and EN standards is based solely on the concept of mineralization to CO2, materials containing lignin can receive poor values in these tests. The implications of this for standardized requirements of biodegradability and possible options to overcome testing deficiencies are discussed.

Automatic test paper design is critical in education to reduce workloads for educators and facilitate an efficient teaching process. However, current designs fail to satisfy the realistic teaching requirements of educators, including the consideration of both test quality and efficiency. This is the main reason why teachers still manually construct tests in most teaching environments. In this paper, the quality of tests is quantitatively defined while considering multiple objectives, including a flexible coverage of knowledge points, cognitive levels, and question difficulty. Then, a model based on the technique of linear programming is delicately designed to explore the optimal results for this newly defined problem. However, this technique is not efficient enough, which cannot obtain results in polynomial time. With the consideration of both test quality and generation efficiency, this paper proposes a genetic algorithm (GA) based method, named dynamic programming guided genetic algorithm with adaptive selection (DPGA-AS). In this method, a dynamic programming method is proposed in the population initialization part to improve the efficiency of the genetic algorithm. An adaptive selection method for the GA is designed to avoid prematurely falling into the local optimal for better test quality. The question bank used in our experiments is assembled based on college-level calculus questions from well-known textbooks. The experimental results show that the proposed techniques can construct test papers with both high effectiveness and efficiency. The computation time of the test assembly problem is reduced from 3 hours to 2 seconds for a 5000-size question bank as compared to a linear programming model with similar test quality. The test quality of the proposed method is better than the other baselines.

In the era of Industry 4.0, digital transformation has spurred the swift advancement of technologies, including intelligent predictive maintenance scheduling, prognostics and health management. The accurate prediction of remaining useful life plays a crucial role in these technologies as it extends power equipment’s safe operational duration and decreases the maintenance costs associated with unforeseen shutdowns. Also, the increased accessibility of data for monitoring system conditions has paved the way for the more immense adoption of machine learning models in prognostics and health management for power transformers. At the moment, with the ever-increasing demand for electricity, there is a corresponding increase in the degradation processes of power transformers. Transformers insulation system and more importantly, the paper insulation happens to be the principal part where the degradation is prominent. Therefore, an accurate prediction of the insulating paper condition through its degree of polymerization is required to guarantee the reliability of power transformers. In this regard, the predictions, reliability, and health monitoring of this power equipment can be actualized by modeling the degradation of transformer insulation paper through several machine learning frameworks. In this view, this review paper has been drafted not only to serve as a guide for researchers interested in the fields of transformer insulation system fault prognosis but also to offer insights into potential research directions as existing literature in modeling and evaluating transformer paper insulation is presented.

To improve the accuracy and efficiency of the aging life prediction and assessment of transformer oil-paper insulation, and to make up for the deficiencies of traditional characterizers, such as 2-furfural, carbon monoxide, and carbon dioxide, a method for the simultaneous determination of methanol, ethanol, $n-\mathbf{propanol}$, and $n$-butanol in oil with a single injection is established by headspace-gas chromatography-mass spectrometry. The measured results show that the determination limits of the four alcohol characterizers can be controlled to $\mathbf{10}\ \mu \mathbf{g}/\mathbf{kg}$ level. Based on this method, the change patterns of the above four alcohols with thermal aging time and degree of polymerization are obtained through thermal aging experimental research. Ethanol, $n$-propanol, and $n$-butanol in oil indicate nearly linear correlations with thermal aging time and degree of polymerization, similar to that of methanol. By analyzing 52 sets of measured data of 500 kV EHV transformers in operation, $n$-butanol is found to have excellent performance, and a new method to evaluate the aging state of oil-paper insulation employing $n$-butanol and methanol is proposed along with the aging attention value model. The measured data of 500 kV EHV transformers in operation indicate that the combination of $n$-butanol and methanol as the preferred characterizers can effectively compensate for the shortcoming of traditional characterizers in the early stages of aging, and the feasibility of the method is verified. Two possible pathways for the generation of $n$-butanol by cellulose cleavage during the aging of oil-paper are proposed from the chemical structure of cellulose.

The current study is related to fabrication of point-of-care molecularly imprinted paper-based analytical devices, specifically related to ovarian cancer early stage detection. The task involves creating a paper coated with silver nanoparticles (AgNPs) that can be used as a transducer via surface enhanced Raman spectroscopy (SERS) to detect the threshold level of the biomarker lysophosphatidic acid (LPA) as a template molecule to diagnose ovarian cancer. MIPs are synthetic receptors designed for a targeted molecule which are prepared from polymers in the presence of target such as small molecules, proteins or cells etc. Removal of the template results in cavities which are structurally and electrostatically complementary to the template molecule. The molecularly imprinted polymer (MIP) layer was anchored on vinyl trimethoxy silane modified-paper, which served as a detector by hydrolytically modifying the paper surface with vinyl trimethoxy silane. To detect LPA in serum samples for ovarian cancer, MIP-paper based on SERS was developed. Patients with benign ovarian tumors had an LPA level of 7.73 μM whereas those with ovarian cancer have a level of 16.99 μM. A healthy person's LPA level is 2.92 μM. Consequently, the rise in LPA levels may aid in the early detection of ovarian cancer. The study refers to the use of a point of care device to diagnose ovarian cancer early, which should be simple, effective, and cost-effective. The analytical tool in the study is a sensor with high selectivity and sensitivity, quick assay times, and inexpensive costs. For LPA in serum, the binding constant of modified paper-based MIP ranges from 11.00 μM to 0.08 μM. The amalgamation of nanoparticles on 2D-paper with MIP have lead to develop sensor which can effectively select LPA in untreated real samples like serum.

Evaluating the long-term influence of academic papers in the early stage after publication is crucial for research management and decision-making. Although the total number of citations has been considered as a valid indicator to measure the academic influence of papers, there are still some bottleneck problems in predicting future citation counts. Firstly, it remains a challenging task to select the reasonable features due to the diversity of model features. Secondly, some prediction models are overly complex and their defects may cause prediction bias or even errors. Finally, the most important thing is that very few models possess long-term predictive ability. This paper proposes a prediction model that can provide an early evaluation of the long-term citations, or the long-term influence, of academic papers. The model uses features available immediately after publication or after a certain period of time. Taking academic papers in Information Science and Library Science as our experimental subject, we train the model using three machine learning algorithms and find that the artificial neural network performs satisfactorily. Our findings may offer guidance for research management and decision-making.

Extant studies have focused on exploring the research output of universities in Nigeria, but the measure of the quality of research output using citations per paper (CPP) from the Web of Science (WoS) and Scopus is scarcely discussed. This paper investigated the quality of papers published by the top 76 universities in Nigeria. Five hypotheses on CPP were tested using Kruskal-Wallis and Mann-Whitney tests. These hypotheses tested whether CPP is the same or different i) across six geo-political regions (GPRs), ii) between the two major regions, iii) across three university funding types, iv) in Scopus and WoS, and v) if these two databases are correlated. Results using these two databases indicated that no significant median differences were detected among universities across the six GPRs, between northern and southern Nigeria, and between the three funding types (federal, state, and private). Moreover, no significant median differences in CPP between Scopus and WoS were detected, and CPP in both databases was highly positively correlated (0.879; p = 0.05). A comparison of the mean CPP of Nigeria (5.90) from Scopus with 57 other African countries ranked it 47th despite being ranked third in terms of volume of published articles. Policy prescriptions are made on the implications of using CPP for practice.

Poly(3-hydroxybutyrate) (PHB), a biodegradable polymer, has been studied as a substitute for petroleum-based polymers used for barrier coating to improve the barrier and mechanical properties of paper. In this study, ethyl cellulose (EC), a cellulose derivative, was used to prepare a polymer blend for enhancing the barrier properties of PHB. The prepared PHB/EC blend was then applied as a paper coating material. Additionally, the barrier and mechanical properties of the PHB/EC blend-coated paper based on the PHB/EC mixing ratio and coating weight were analyzed. The results showed that the EC could act as a binder for the PHB/EC blend-coated paper. Consequently, the PHB/EC blend-coated paper exhibited significant improvements in mechanical and barrier properties, including a substantial increase of over 100% in internal bond strength, more than 20% in tensile strength, exceeding 60% enhancement in water resistance, and a remarkable increase of over 90% in air permeability.

Herein, the challenge of accurately classifying the manufacturing origin of printing paper, including continent, country, and specific product, was addressed. One-dimensional convolutional neural network (1D CNN) models trained on infrared (IR) spectrum data acquired from printing paper samples were used for the task. The preprocessing of the IR spectra through a second-derivative transformation and the restriction of the spectral range to 1800 to 1200 cm-1 improved the classification performance of the model. The outcomes were highly promising. Models trained on second-derivative IR spectra in the 1800 to 1200-cm-1 range exhibited perfect classification for the manufacturing continent and country, with an impressive F1 score of 0.980 for product classification. Notably, the developed 1D CNN model outperformed traditional machine learning classifiers, such as support vector machines and feed-forward neural networks. In addition, the application of data point attribution enhanced the transparency of the decision-making process of the model, offering insights into the spectral patterns that affect classification. This study makes a considerable contribution to printing paper classification, with potential implications for accurate origin identification in various fields.

Ultra high frequency (UHF) partial discharge (PD) detection is a common method for transformer oil-paper insulation defect location. However, the accuracy of PD positioning in practical application is easily affected by noise and sensor layout. In order to ensure the effectiveness of PD positioning detection of transformer oil-paper insulation defect, an UHF PD positioning detection platform for oil-paper insulation defects is established. Based on the conventional K-means method, a modified clustering demarcation PD anti-interference positioning method is proposed, which effectively reduces the positioning error. Aiming at the problem of sample clustering demarcation aliasing, when the optimal correction coefficient L is 1.1, the UHF PD positioning error can be reduced to less than 0.1 m, which verifies the effectiveness of the proposed method. Finally, the variation law of positioning error of different sensor layout is analyzed, and the optimal layout scheme of UHF sensor for transformer oil-paper insulation defect detection is proposed, which can provide reference for the layout and positioning of transformer on-line monitoring sensor.

This current study aimed to investigate rural college EFL students’ experiences in dealing with English research paper writing and publication barriers. Five senior EFL students voluntarily participated in a photovoice phenomenological study. The data were collected through two methods, including semi-structured interviews and a photovoice. The students took some emotional photos to express their feeling on paper writing and publication barriers visually. The interviews encouraged them to describe their experiences and feelings through the photos. The data were analyzed by synchronizing each photo with its qualitative description. As for the results, it is noted that there were three main paper writing and publication barriers, including a lack of linguistic competence, being trapped with a journal template, and anxiety towards written corrective feedback. Each interview result was accomplished with emotional photos in several themes such as untidy pieces of paper, scenery, internet search, children’s toys, colourful pens, and empty box. The photos were also supported by qualitative remarks of each EFL student. In short, the photovoice helps to represent deep feelings on the research paper writing and publication barriers experienced by the EFL students.

Antiseptic paper soap is convenient because it is flexible, safe for the skin, easily foams, and relatively affordable. Measuring the ratio between the concentrations of NaOH, cooking oil, citronella oil, and aloe vera additives is needed to improve the quality of antiseptic paper soap. Testing the saponification rate, density, pH, water content, fatty acid (FA) level, and free alkali content is critical to determine the characteristics of antiseptic paper soap so that it meets the standards for solid bath soap according to SNI 3532-2021 which is closest to the characteristics of paper soap because SNI for paper soap is not yet available. The weight ratio of citronella oil to cooking oil used is 1:1, 1:2, and 1:3. The NaOH concentrations used were 30%, 40%, and 50% w/v. The natural additives used are 0%, 5%, and up to 10% of the total mass. The research results showed that saponification value of the antiseptic paper soap produced was 197.724 milligrams KOH/gram up to 206.138 milligrams KOH/gram, the pH of the antiseptic paper soap was 9.1-10.6, the water content value was 10.940%-23.863%, the alkali content value free is 0.044%-0.104%, total fatty acid (FA) content is 29.688%-45.734%. The best antiseptic paper soap is produced using 30% w/v NaOH with a weight ratio of citronella oil to cooking oil used of 1:1 and natural additives (aloe vera) 5% of the total mass.

The results of research on physical and chemical methods for the preliminary treatment of wastewater of a cardboard and paper factory in Khmelnytskyi region of Ukraine are presented. At the cardboard and paper factory, wastewater is treated at a sewage treatment plant, which includes sand traps, primary radial sedimentation tanks, aeration tanks with activated sludge regenerators, secondary radial sedimentation tanks, and bioponds. The use of coagulation and chlorination methods before biological treatment in aeration tanks was proposed. Alumoflock 18% was used as a coagulant, polyacrylamide was used as a flocculant, and sodium hydroxide was used as an alkalizing reagent. The study was conducted on a mixture of industrial and domestic wastewater with COD and BOD5 – 3200 and 1575 mg/dm3, respectively, and on industrial wastewater with COD and BOD5 – 4480 and 1960 mg/dm3, respectively. The effects of reducing COD and BOD5 indicators in the first case after coagulation were 30 and 40%, after chlorination - 37.81 and 43.17%, respectively, in the second after coagulation - 28.57 and 47.24%, respectively. It was established that a significant proportion of organic substances according to the COD indicator is in a dissolved state - 60-70%. It has been proven that as a result of chlorination, the maximum reduction of "pure" COD is achieved, therefore, the possibility and expediency of chlorination of water after the secondary settling tank with increased doses should be considered in the wastewater treatment technology of the cardboard and paper factory.

Due to the high wastepaper recyclability and water-loop system closure, packaging paper mills struggle with increased fines, causing runnability issues. Cellulase enzymes are a preferred treatment choice for the improvement of the pulp refining in stock preparation area but are not widely used or easy to introduce in the production process. Different cellulase enzymes were tested, and those with the highest activity were introduced to the white-water (WW) samples with the aim to reduce fines content as potentially new enzyme applications on the paper machine. The first portion of the study involved the development of an experiment model to find and confirm the optimal enzyme process parameters (40 °C, pH 5.7, reaction time 3 h, and 0.18% v/v enzyme addition) for laboratory made white-water. The second portion of the study included turbidity, colloidal charge, flow cytometry (FCM), and chemical oxygen demand (COD) analysis on industrial and laboratory made white-water samples at optimized process parameters. Obtained results corresponded to reduced fines content in white-water samples, which justified commercial usage of cellulase enzymes on recycled paper machine short loop and potentially increased machine runnability without negative influence on wastewater treatment plant.

In this research, I established an energy benchmark for the pulp and paper industry of Vietnam. I, therefore, focus on three major paper product families, including packaging paper, printing and writing paper, and tissue paper. In this research, I use specific energy consumption (SEC) as the energy performance indicator (EnPI) for computing energy benchmarks for the main sub-sectors in the pulp and paper industry of Vietnam. The factories in the pulp and paper industry of Vietnam are divided into three production scales, and the energy benchmarks are specified by production scales. Energy surveys and energy audits have been used to calculate energy benchmarks. Here, I establish the energy benchmark for the main sub-sectors in the pulp and paper industry of Vietnam according to the three production scales. I also estimate the energy saving potential for the pulp and paper industry of Vietnam based on surveying and auditing results.

Teachers use many methods to measure students' progress in learning Arabic, either by using a computer or manually. This study aimed to determine the level and comparison between student motivation to complete assignments using computer-based and paper-based test methods in Arabic language learning. This research used a quantitative approach with comparative descriptive by performing observation, questionnaire, and interview for data collection. It used data analysis methods, such as validity tests, reliability tests and percentage analysis. The research subjects were 23 tenth graders of Visual Communication Design of SMK Muhammadiyah 2 Malang. The results of this study are: (1) the motivation of students to complete Arabic language assignments by computer-based test methods is 81.13% with high category. (2) The motivation of students to complete Arabic language assignments by paper-based test method is 83.82% with high category. (3) Comparison between the motivation of students to complete assignments using computer and paper-based test methods is 2.7% with low category. This difference is due to several factors, including human resource factors. This research has contributed to the Arabic language learning evaluation as it can be used as a teacher's consideration on what methods to use.

Abstract Some ancient Chinese paper artifacts dyed with amur cork tree bark extracts are currently preserved to different extents in museums and libraries worldwide. As traditional natural plant dyes, the long-term performance of the amur cork tree bark extract-dyed handmade paper has been questioned under a preserved environment. The photodegradation process of the extract-dyed papers was examined under accelerating artificial UVA irradiation conditions according to China national standard-paper and board- accelerated aging (exposure to light). Changes during aging were analyzed by optical observation and scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR), pH, and tensile strength and folding endurance tests. The results showed that the main components from extracted dyes played an important role in affecting the photodegradation properties of dyed paper. The changes in surface color, pH, morphology and mechanical properties after the artificial UVA accelerated degradation tests revealed that a suitable concentration of the extract dyes for maintaining the long-term irradiation stability of the paper is important.

Abstract Background Undergraduate STEM instructors want to help students learn and retain knowledge for their future courses and careers. One promising evidence-based technique that is thought to increase long-term memory is spaced retrieval practice, or repeated testing over time. The beneficial effect of spacing has repeatedly been demonstrated in the laboratory as well as in undergraduate mathematics courses, but its generalizability across diverse STEM courses is unknown. We investigated the effect of spaced retrieval practice in nine introductory STEM courses. Retrieval practice opportunities were embedded in bi-weekly quizzes, either massed on a single quiz or spaced over multiple quizzes. Student performance on practice opportunities and a criterial test at the end of each course were examined as a function of massed or spaced practice. We also conducted a single-paper meta-analysis on criterial test scores to assess the generalizability of the effectiveness of spaced retrieval practice across introductory STEM courses. Results Significant positive effects of spacing on the criterial test were found in only two courses (Calculus I for Engineers and Chemistry for Health Professionals), although small positive effect sizes were observed in two other courses (General Chemistry and Diversity of Life). Meta-analyses revealed a significant spacing effect when all courses were included, but not when calculus was excluded. The generalizability of the spacing effect across STEM courses therefore remains unclear. Conclusions Although we could not clearly determine the generalizability of the benefits of spacing in STEM courses, our findings indicate that spaced retrieval practice could be a low-cost method of improving student performance in at least some STEM courses. More work is needed to determine when, how, and for whom spaced retrieval practice is most beneficial. The effect of spacing in classroom settings may depend on some design features such as the nature of retrieval practice activities (multiple-choice versus short answer) and/or feedback settings, as well as student actions (e.g., whether they look at feedback or study outside of practice opportunities). The evidence is promising, and further pragmatic research is encouraged.

Hemp hurd fiber, a low-value waste stream from the hemp industry, has potential downstream applications as an alternative to non-renewable plastics for single-use food service ware and packaging applications. Packaging paper substrates made from chemically pulped hemp hurd, mixed in varying ratios with bleached thermomechanical radiata pine pulp were developed and tested. Handsheets were characterized using several mechanical property tests including tensile strength, tearing resistance, burst strength, short-span compression, ring crush, together with Gurley air resistance, contact angle, and Cobb60 tests. Generally, addition of hemp hurd fibers significantly improved handsheet mechanical properties. Hot-pressing of the handsheets so as to approximate molded fiber thermoforming further enhanced their performance, with pure hemp hurd handsheets having the highest mechanical properties and barrier performance. A prototype was successfully thermoformed from hemp fiber, demonstrating overall feasibility of this fibre source for molded fibre objects.

The instructions to authors about the article preparation for publication in the Military Technical Courier are based on the Regulations on categorization and ranking of scientific journals of the Ministry of Education, Science and Technological Development of the Republic of Serbia (Official Gazette of the Republic of Serbia, No 159/20). This Regulations aims at improving the quality of national journals and raising the level of their compliance with the international system of scientific information exchange. The editorial policy of the Military Technical Courier is based on the COPE Core Practices, common COPE, DOAJ, OASPA and WAME Principles of Transparency and Best Practice in Scholarly Publishing as well as on the best accepted practices in scientific publishing. The Military Technical Courier has been a COPE (Committee on Publication Ethics) member since 2nd May 2018 and a member of OASPA (Open Access Scholarly Publishers Association) since 27th November 2015. The editorial office applies Checklist for open access publishers on implementing the UNESCO Recommendation on Open Science. This document is part of the UNESCO Open Science Toolkit, designed to support implementation of the UNESCO Recommendation on Open Science. It has been produced in partnership with OASPA.

The Bündnis Junger Ärztinnen und Ärzte (BJÄ, Alliance of Young Physicians in Germany) has presented a position paper (PP) on Postgraduate Medical Education (PGME) against the background of an unfolding hospital reform in Germany, and they describe existing deficits of PGME in Germany. Based on this, demands were made of legislators, employers and medical associations which could result in a sweeping reformation of PGME. Hospital reforms can only be accomplished with well trained and motivated physicians. In this respect the BJÄ regards the reform of hospitals and the health-care system as a chance for a reform of PGME, which is long overdue. Legislative competence for PGME lies with the States of the Federal Republic of Germany and this warrants an adjustment of state medical association laws to accommodate the demands of the BJÄ. Generally PGME must be taken into consideration in all health-care legislation, in analogy to the meanwhile globally adopted principle of “Health in all Politics (HiAP)”. The BJÄ has made every endeavour to produce this PP. The responsible stakeholders and actors in the health-care system would be well-advised to take the position paper seriously with a dwindling physician work force in hospitals and serious quality deficits in PGME. Hence, the BJÄ must be comprehensively supported. They need congenial partners to define the scientific foundation of all their demands, to test their application under real life conditions in hospital and outpatient care, to pursue research on the impact on patient care and on the intended transformation of the health-care system. This might best be accomplished by partnering with a scientific as has been the case in many countries for decades.

Abstract Oil‐paper insulation material is an essential component for oil‐filled transformers, and polyimide (PI) insulation paper is a novel material in the field of electricity. The improvement of insulation class for insulation paper has gained significant attention in recent years. In this study, SiO2 nanoparticles were modified with a silane coupling agent (KH550), and the KH550‐SiO2 was added to the fibre membrane through in situ polymerisation. The chemical composition and microcosmic characteristics of the PI porous fibre membrane were characterised using FT‐IR and SEM FT‐IR and SEM. Consequently, the dielectric constant of the composite paper was reduced to 2.3 upon adding 3 wt% of KH550‐SiO2, and the dielectric strength reached its maximum value of 85 kV/mm. The results demonstrate that the insulation performance of the KH550‐SiO2/PI composite was significantly improved due to the incorporation of nano‐SiO2. This establishes an efficient approach for achieving excellent electrical and thermal properties in practical applications using the KH550‐SiO2/PI fibre membrane.

Abstract The moisture generated by the ageing of the oil‐paper insulating system can easily lead to the deterioration of the performance of the insulating paper. In order to alleviate the impact of moisture on the performance of the insulating paper, we developed a kind of lipophilic hydrophobic self‐repairing cellulose insulating paper (new insulating paper) based on the ternary system of polytetrafluoroethylene, fluorocarbon surfactant and fluorinated alkyl silane, and accelerated thermal ageing test for 45 days at 130°C was carried out. The experimental results show that the new insulating paper with excellent lipophilic property can realise hydrophobic self‐repairing through heat treatment after physical damage. The tensile strength and elongation at break of the new insulating paper increased by 5%–8% and 6.25%–27% respectively compared with the original cellulose insulating paper. At the end of ageing, the relative dielectric constant and dielectric loss factor of new insulating paper are 10.4% and 9.9% lower than that of the original cellulose insulating paper, while the breakdown voltage is 6.8% higher. The acid and moisture content produced during the ageing process of the insulating oil impregnated with new insulating paper are also less, indicating that the coating can delay the ageing of the insulating paper.

Abstract Background In response to the imperative need for standardized support for adolescent Gender Dysphoria (GD), the Italian Academy of Pediatrics, in collaboration with the Italian Society of Pediatrics, the Italian Society for Pediatric Endocrinology and Diabetes, Italian Society of Adolescent Medicine and Italian Society of Child and Adolescent Neuropsychiatry is drafting a position paper. The purpose of this paper is to convey the author's opinion on the topic, offering foundational information on potential aspects of gender-affirming care and emphasizing the care and protection of children and adolescents with GD. Main body Recognizing that adolescents may choose interventions based on their unique needs and goals and understanding that every individual within this group has a distinct trajectory, it is crucial to ensure that each one is welcomed and supported. The approach to managing individuals with GD is a multi-stage process involving a multidisciplinary team throughout all phases. Decisions regarding treatment should be reached collaboratively by healthcare professionals and the family, while considering the unique needs and circumstances of the individual and be guided by scientific evidence rather than biases or ideologies. Politicians and high court judges should address discrimination based on gender identity in legislation and support service development that aligns with the needs of young people. It is essential to establish accredited multidisciplinary centers equipped with the requisite skills and experience to effectively manage adolescents with GD, thereby ensuring the delivery of high-quality care. Conclusion Maintaining an evidence-based approach is essential to safeguard the well-being of transgender and gender diverse adolescents.

Abstract Avoiding financial losses requires preventing catastrophic oil‐filled power transformer breakdowns. Continuous online transformer monitoring is needed. The authors use paper insulation to evaluate transformer health for continuous online transformer monitoring. The study suggests a new artificial intelligence method for estimating paper insulation residual life in oil‐immersed power transformers. The four artificial intelligence models use backpropagation‐based neural networks to predict paper insulation lifespan. Four primary transformer insulating paper failure indices—degree of polymerisation, 2‐furfuraldehyde, carbon monoxide, and carbon dioxide—form the basis of these models. Each model, including the backpropagation‐based neural networks, estimates paper insulation life using one failure index, along with moisture and temperature data. Optimisation techniques enhance hidden layer neurons and epoch count for improved performance. Results are validated against literature‐based life models, establishing a precise input–output correlation. This method accurately predicts the remaining useable life of power transformer paper insulation, enabling utilities to take proactive measures for safe and efficient transformer operation.

Abstract Anger suppression is important in our daily life, as its failure can sometimes lead to the breaking down of relationships in families. Thus, effective strategies to suppress or neutralise anger have been examined. This study shows that physical disposal of a piece of paper containing one’s written thoughts on the cause of a provocative event neutralises anger, while holding the paper did not. In this study, participants wrote brief opinions about social problems and received a handwritten, insulting comment consisting of low evaluations about their composition from a confederate. Then, the participants wrote the cause and their thoughts about the provocative event. Half of the participants (disposal group) disposed of the paper in the trash can (Experiment 1) or in the shredder (Experiment 2), while the other half (retention group) kept it in a file on the desk. All the participants showed an increased subjective rating of anger after receiving the insulting feedback. However, the subjective anger for the disposal group decreased as low as the baseline period, while that of the retention group was still higher than that in the baseline period in both experiments. We propose this method as a powerful and simple way to eliminate anger.

The article introduces attraction marketing methods employed by Russian monthly popular science magazine Diletant. The authors compared the printed version and the website. The paper magazine attracts the reader mainly by the topic name printed on its cover as a unique creolized text. The further semantics of the front media text includes various aspects of the main topic. Color highlights both topical issue and regular features. The comparative analysis with the online version revealed some significant differences. The website has a muted color scheme and minimal animation; it contains neither video nor audio materials. Like in the printed version, the function of attraction belongs mainly to illustrations and subtitles. Online Diletant is interactive in navigation, tests, and surveys, which are, however, the only form of interactivity: the site does not provide comments, forums, “likes”, etc. Such limited use of attention-seeking tools makes the digital version of Diletant uncompetitive and inferior to its paper issue.

The effects of the pre-coating color formulation, dwell time, and coat weights of pre- and top- coating layers on print mottle of double-coated paper were investigated using an octave band filtering image processing technique. To investigate the effect of pre-coating color formulations, six types of coating colors were used. Mottle index and coefficient of variance (COV) of double-coated paper increased as the size of pre-coating pigment particles decreased, which was attributed to the reduction in relative pore size of the pre-coating layer. Decreasing the dwell time decreased transfer time from the coating head to dryer of a Maiyoh coater. As the transfer time to dryer decreased, the mottle index and COV increased because of uneven distribution of latex within the coating layer. Pre-coat weight was found to have a greater impact on print mottle than the top-coat weight.

The influences of nano-chitosan and cationic polyacrylamide (cPAM) on the optical and mechanical properties of paper made from chemi-mechanical pulp (CMP) were investigated. Bleached chemi-mechanical pulp (CMP) was selected as the control sample. The cPAM was considered at four levels (0%, 0.25%, 0.5%, and 0.75%), while chitosan was added to the CMP suspension at three levels (0%, 1%, and 2%). Paper test specimens were prepared according to TAPPI standards with a basis weight of 60 g/m2, and their optical and mechanical properties were measured. The results indicated that the opacity, greenness, tear strength, burst strength, and Gurley seconds were increased, whereas brightness, water absorption, and a* factor were decreased by increasing the amount of cPAM. Adding chitosan to CMP increased the a* factor, tear strength, breaking length, burst strength, Gurley seconds, water absorption, and greenness in the resulting paper. When polyacrylamide and nano-chitosan were added simultaneously to CMP, the brightness, water absorption, and greenness of the resulting paper decreased, but opacity, burst strength, tear strength, and air resistance had an appropriate increase. In all treatments, the best results were found at 1% chitosan and 0.5% cPAM due to favorable optical and mechanical properties.

This article substantiates the possibilities of replacing commercial wood with raw materials made from industrial hemp hurd (hemp-woody core) for the production of unbleached and bleached paper pulps. A comparative analysis of the mechanical characteristics of sheets of paper prepared in the Rapid-Köthen apparatus and obtained from pulp obtained from commercial wood and hemp-woody core (HWC) was undertaken. The objective of this study was to determine the effect of mechanical refining of a pulp on the production of microcrystalline cellulose (MCC) from HWC. It was shown that an increase in the pulp refining degree from 15 °SR to 83 °SR led to a decrease in the degree of polymerisation of MCC from 272 to 75, the hydrochloric acid concentration from 73 to 45.63 g/L, and the hydrolysis time from 120 min to 60 min. With the addition of 5% MCC obtained from hemp-woody core, the mechanical properties of laboratory paper sheets from HWC were improved until they met ISO 12625-4-2017 (2017) requirements for NS-2. The results obtained support using hemp-woody core for the production of MCC.