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Foam-assisted web forming and chemical application technologies have great potential to improve manufacturing efficiency and product quality in the paper and nonwovens industries. In this study, the benefits of foam forming and foam-assisted application of chemicals were demonstrated in a pilot machine trial. Uniform high-bulk webs of unrefined bleached softwood kraft pulp (BSKP) and viscose fibers were manufactured by foam forming. It was shown that foam formed low-grammage and high-bulk viscose fiber webs can be strengthened by foam-assisted application of latex onto the wet web. Correspondingly, foam-assisted application of carboxymethyl cellulose (CMC) and anionic polyacrylamide (A-PAM) improved the strength of the foam formed low-grammage and high-bulk BSKP web. Overall, the pilot machine results indicated that material cost savings could be achieved and a high-performance product could be manufactured with foam-based technologies.

Cellulose-based materials represent a renewable, biodegradable, and environmentally friendly alternative to plastic from fossil resources. Nanopaper is a strong and lightweight material formed from cellulose nanofibrils (CNFs). Paper and nanopaper have been considered as excellent alternatives to plastics for use in agriculture and for packaging applications. However, common for both paper and nanopaper is their hydrophilic character, and consequently, poor water-resistance properties. ORMOCER®s are a class of inorganic–organic polymers with excellent barrier and protective properties used for a range of coating applications. Here we present ORMOCER®-coated paper and nanopaper. The coated papers and nanopapers are characterized, both in terms of their morphology, hydrophobicity, and mechanical properties. We demonstrate that the pressure used during the pressing and drying of paper and nanopaper influence their tear and tensile—properties, and that the morphology of the coated nanopaper differs significantly from that of the coated paper. While the ORMOCER® was impregnated within the porous network of the paper, a well-defined two-layered morphology was obtained with the coated nanopaper. Further, the biodegradability of the nanopaper with and without coating was assessed. The degradation study demonstrated that both the pressure used during the pressing and drying of the nanopaper, and the composition of the ORMOCER®, influenced the rate of degradation. Taken together, ORMOCER®-coated paper and nanopaper are promising for the preparation of materials that are both water-resistant, renewable, and biodegradable.

This study looked at how using small or large pieces of Rice Husk Ash and Waste Paper Sludge Ash can affect how strong and how much the concrete shrinks when it dries. When Rice Husk Ash (RHA) and Waste Paper Sludge Ash (WPSA) were added to concrete, more water was needed. However, the mechanical properties of the concrete were similar or better than the concrete made with just Ordinary Portland Cement (OPC). Finer RHA and WPSA gave the best improvements. Rice husk and waste paper ash made things shrink a lot because of tiny particles that cause it to happen. This research looked at using waste paper sludge ash instead of some of the cement in a kind of concrete called M20 mix. They tested different amounts of the ash (0%, 5%, 10%, 15%, 20%, and 25%) to see how strong it made the concrete. They tested the strength of the concrete up to 28 days after it was made and compared it to normal concrete. Waste paper sludge can be used as fuel because it has a lot of heat energy. Afterwards, the remaining ash can be used to replace some of the cement.

We propose a unique form of dye-sensitized solar cells (DSSCs), paper DSSCs based on carbon-nanotube (CNT) composite papers, and the use of a gel electrolyte for the paper DSSC. In our previous study, we succeeded in developing the paper DSSC. However, its performance and lifetime were not sufficient. We considered that the problem was the use of liquid-type electrolyte. To improve the performance of the paper DSSC, a gel electrolyte was introduced to increase safety and durability. Here, a polymer gel electrolyte was synthesized using a copolymer of polyethylene glycol (PEG) and polyvinylidene fluoride (PVDF) as a matrix, mixed with iodine and potassium iodide. The resulting paper DSSC had a fill factor (FF, a performance indicator) of 0.248 and a conversion efficiency of 2.43 × 10−5% with an extended working time (lifetime) of more than 110 min. Further modifications were made to the metallic CNT composite paper and the gel electrolyte, resulting in an increased conversion efficiency of 2.02 × 10−3%. This study suggests the potential of gel electrolytes in enhancing the performance of paper DSSCs, providing new insights for their future applications.

The aim of this study is to propose a test method for the determination of the quality of transformer paper insulation. For this purpose, the oil/cellulose insulation systems were exposed to various accelerated aging tests. The results of the aging experiments of normal Kraft and thermally upgraded papers, two different types of transformer oil (mineral and natural ester), and copper are shown. Aging was carried out in various experiments at 150 °C, 160 °C, 170 °C, and 180 °C with dry (initial values ≤ 0.5%) and moistened cellulose insulation (initial values 3–3.5%). Following insulating oil and paper, degradation markers were measured: the degree of polymerization, tensile strength, furan derivates, methanol/ethanol, acidity, interfacial tension, and dissipation factor. It was found that the aging of cellulose insulation in cycles was 1.5–1.6 times faster in comparison to continuous aging, due to the more pronounced effect of hydrolytic mechanism in cyclic aging owing to the produced and absorbed water. Furthermore, it was observed that the high initial water content in cellulose increases the aging rate two to three times more than in the dry experimental setup. The proposed aging test in cycles can be used to achieve faster aging and to compare the quality of different insulating papers.

Purpose: The aim of this research work is to analyze and compare profitability performance of selected paper companies in India. Approach/Methodology/Design: An analytical study method is employed in this research work by relying on secondary data. In this research work 12 paper companies are selected as a sample based on their higher net sales and the study period are last10 financial years from 2012-13 to 2021-22. Ratio Analysis is used as an accounting tool in which six profitability ratios are employed. One-way ANOVA technique of parametric test is used as a statistical tool to identify the difference among sample means. Findings: The major finding of the research work indicates that in all the selected paper companies the profitability performance of shows fluctuating trend during the study period of 10 years. The overall performance was good and satisfactory in Satia Industries Ltd., JK paper Ltd., Seshasayee Paper and Board Ltd. and NR Agarwal Industries Ltd. and it was low and dissatisfactory in Orient Paper & Industries Ltd. and Astron Paper & Board Mill Ltd. for all the selected profitability ratio during the study period. The results of statistical test revealed that in gross profit ratio, operating profit ratio and return on assets ratio formulated null hypotheses are rejected and in net profit ratio, return on net worth ratio and return on capital employed ratio formulated null hypotheses are accepted. Originality/value: In this research work profitability analysis is carried out which is helpful to know the profitability performance of selected paper companies. The result would help investors to make right choice of investment in selected companies. It would also identify that how efficiently a business can generates profit and value for its shareholders from its sales or operations, shareholders' fund or balance sheet’s assets.

Currently, tissue product producers try to meet consumers’ requirements to retain their loyalty. In perforated products, such as toilet paper, these requirements involve the paper being portioned along the perforation line and not outside of it. Thus, it becomes necessary to enhance the behavior of the perforation line in perforated tissue papers. The current study aimed to verify if the perforation line for 0° (the solution found in commercial perforated products) is the best solution to maximize the perforation efficiency. A finite element (FE) simulation was used to validate the experimental data, where the deviations from the experiments were 5.2% for the case with a 4 mm perforation length and 8.8% for a perforation of 2 mm, and optimize the perforation efficiency using the genetic algorithm while considering two different cases. In the first case, the blank distance and the perforation line angle were varied, with the best configuration being achieved with a blank distance of 0.1 mm and an inclination angle of 0.56°. For the second case, the blank distance was fixed to 1.0 mm and the only variable to be optimized was the inclination angle of the perforation line. It was found that the best angle inclination was 0.67°. In both cases, it was verified that a slight inclination in the perforation line will favor partitioning and therefore the perforation efficiency.

Bacterial nanocellulose (BNC), due to its inherent nanometric scale and strength properties, can be considered as a good candidate to be used in papermaking. This work explored the possibility of using it in the production of fine paper as a wet-end component and for the paper coating. Filler-containing handsheet production was performed with and without the presence of common additives typically used in the furnish of office papers. It was found that, under optimized conditions, BNC mechanically treated by high-pressure homogenization could improve all the evaluated paper properties (mechanical, optical and structural) without impairing the filler retention. However, paper strength was improved only to a small extent (increase in the tensile index of 8% for a filler content of ca. 27.5%). On the other hand, when used at the paper surface, remarkable improvements in the gamut area of >25% in comparison to the base paper and of >40% in comparison to only-starch coated papers were achieved for a formulation having 50% BNC and 50% of carboxymethylcellulose. Overall, the present results highlight the possibility of using BNC as a paper component, particularly when applied at the paper substrate as a coating agent aiming at improving printing quality., Fundacão para a Ciência e a Tecnologia (FCT), Portugal is acknowledged by SFRH/BDE/108095/2015 grant and Strategic Research Centre Project (UIDB/00102/2020). This work was also carried out under the Project Inpactus - innovative products and technologies from eucalyptus, Project N.º 21874 funded by Portugal 2020 through European Regional Development Fund (ERDF) in the frame of COMPETE 2020 nº246/AXIS II/2017, info:eu-repo/semantics/publishedVersion

In the research of the review of this creative and innovation area that can benefit community and nation. The review that had been picked in this research was the paper. The aim of this review is to explain about the advantages or the benefits of paper and also the used of the paper, also the improvement of the nation by the helps of the paper production and innovation. The methods that we going to describe in this review was the involvement of the paper production in many fields, such as for individuals, schools, medical centre and so on. There are a lot of information and new knowledges that we going to present and cite in this review. The conclusion of this article review was to be making sure that everyone knows the important and the properties of the paper in our country.

Vrsta študij ugotavlja, da likovne dejavnosti prispevajo k razvoju različnega znanja in spretnosti. Študij, ki bi empirično preverjale in dokazovale tovrstno napredovanje, je sicer manj, kar je tudi eden od razlogov udejanjanja naše raziskave. Pestrost likovnih dejavnosti je povezana z različnimi vrstami veščin, zato smo raziskovanje omejili na enega od najpogosteje uporabljanih materialov v predšolskem obdobju, tj. papir. Otroci se v vrtcu vsakodnevno srečujejo in rokujejo s papirjem. Z razvojem fine motorike otroci usvojijo prstne spretnosti, ki so potrebne za obdelavo papirja. To so mečkanje, pregibanje, trganje in uporaba orodij za obdelovanje papirja (škarje in šablona ali ravnilo) (Kurikulum za vrtce, 1999). Nekoliko kasneje k razvijanju drobnih gibov prispeva tudi rezanje in oblikovanje majhnih koščkov papirja. Pri tem imajo pomembno vlogo izkušnje in vaja. Slednja je najučinkovitejša, če je zasnovana v obliki igre. Papir so iz rastlinskih vlaken izdelovali že stari Kitajci, v Evropi pa ga poznamo od 9. stoletja naprej. Papir pridobivajo pretežno iz rastlinskih vlaken, katerim očistijo necelulozne sestavine. Uporaba papirja v likovnih delih je bolj vsestranska, kot si morda mislimo (Čadež-Lapajne, 1983). Vsaka likovna tehnika potrebuje primerno vrsto papirja. Seveda je pri tem pomembnih več lastnosti, od vpojnosti, gramature, pa vse do videza in teksture. Pred uporabo je pomembno, da poznamo osnovne značilnosti papirja. Pri nekaterih likovnih tehnikah pomembno vlogo igra tudi potek vlaken. To vpliva na zgibanje, trganje, rezanje in tudi zvijanje (Brodek, 2013). Akvarelni papir, recikliran papir, papir za origamije in prosojni papir so le nekatere vrste papirja, ki se med seboj precej razlikujejo. V vrtcu so sprva bolj prisotne preproste tehnike obdelovanja papirja, s katerimi razvijamo soročne spretnosti, kot so: mečkanje, trganje, gubanje in pregibanje, kasneje pa tudi rezanje, in lepljenje ter celo prebadanje, luknjanje in spenjanje. Pri rezanju, lepljenju, luknjanju in spenjanju za obdelavo potrebujemo orodja, medtem ko ostale tehnike izvajamo brez orodij. V vrtcu največkrat uporabljamo otroške škarje, škarje z vzorcem, luknjač, spenjač in različna ravnila oziroma šablone (Milčinovič, 1997). Otroške škarje se razlikujejo po velikosti, obliki držala, barvi, dolžini in obliki rezil (imajo zaobljeno rezilo), lahko so desnoročne ali levoročne, nekatere imajo pomagalo za odpiranje škarij, ki olajšajo uporabo. Otroci v vrtcu ravnila uporabljajo redkeje. Poleg klasičnega ravnila poznamo še trikotna ravnila in ravnila krivih oblik za risanje krivih črt. Če imajo ravnila na podlagi prazne prostore, namenjene risanju različnih likov in oblik, jim pravimo šablone. Pri risanju črt z ravnilom je pomembno, da držimo konico svinčnika tik ob stranici ravnila. Ta mora biti nagnjena v smeri, kamor vlečemo črto (Fošnarič, Slukan, Virtič, Puncer, 2004). S pomočjo luknjača v papirnatih gradivih izsekamo odprtino. Poznamo luknjače, s katerimi s pomočjo kladiva na trdi podlagi izsekamo luknjo, in tiste, ki so avtomatski (prav tam). Izbira spenjača je odvisna od števila listov papirja, ki jih želimo naenkrat speti. Namizni pisarniški spenjači lahko spnejo od 2 do 50 listov. Tudi ročni spenjači ali spenjalne klešče spnejo od 2 do 40 listov. Več listov pa lahko spnejo električni spenjači. Za odstranjevanje sponk iz spetega gradiva pa uporabljamo razpenjač. A number of studies have found that art activities contribute to the development of different skills. There are fewer studies that empirically test and prove this kind of progression, which is one of the reasons I decided to investigate it. The variety of art activities is linked to different types of skills, so I have limited my research to one of the most commonly used materials in the preschool period, i.e. paper. Children in kindergarten encounter and handle paper on a daily basis. As children develop fine motor skills, they acquire the finger skills necessary for working with paper: creasing, folding, tearing and the use of paper tools (scissors and a jig or ruler) (Kindergarten Curriculum, 1999). A little later, cutting and shaping small pieces of paper also contributes to the development of fine motor skills (Curriculum for Kindergarten, 1999). Experience and practice play an important role here. The latter is most effective if it is designed in the form of a game. Paper was made from plant fibres by the ancient Chinese and has been known in Europe since the 9th century. Paper is mainly made from plant fibres, which are stripped of their non-cellulosic components. The use of paper in fine art is more versatile than we might think (Čadež-Lapanje, 1983). Each artistic technique needs a suitable type of paper. Of course, several properties are important, from absorbency, grammage, to appearance and texture. Before using it, it is important to know the basic characteristics of the paper. In some fine art techniques, the fibre course also plays an important role. This influences folding, tearing, cutting and even curling (Brodek, 2013). Watercolour paper, recycled paper, origami paper and transparency paper are just some of the types of paper that differ considerably from each other. In kindergarten, simple papermaking techniques are more prevalent at first, which helps us develop related skills such as creasing, tearing, folding and creasing. Later, we develop cutting, gluing and even punching, hole-punching and stapling.Cutting, gluing, punching and stapling require tools, while the other techniques are carried out without tools. In kindergarten, children's scissors, pattern scissors, hole punch, stapler and various rulers or stencils are most commonly used (Milčinovič, 1997). Children's scissors vary in size, shape of handle, colour, length and shape of blades (they have a rounded blade). They can be right-handed or left-handed, and some have a scissor opening aid to make them easier to use. Rulers are less frequently used by children in kindergarten. Beside classic ruler, we also know triangular rulers and curved rulers for drawing curved lines. If rulers have blank spaces on the base for drawing different shapes and figures, they are called stencils. When drawing lines with a ruler, it is important to hold the tip of the pencil right against the side of the ruler. This should be inclined in the direction where the line is drawn (Fošnarič, Slukan, Virtič, Puncer 2004). Using a hole punch helps us to cut an opening in paper materials. There are punches that use a hammer to punch a hole in a hard substrate and those that are automatic (ibid.). The choice of stapler depends on the number of sheets of paper to be stapled at one time. Desktop office staplers can staple from 2 to 50 sheets. Manual staplers or staplers can also staple from 2 to 40 sheets. Electric staplers can staple more sheets. Paper clip remover are used to remove staples from stapled material.

Developing a convenient detection method for dopamine holds a significant incentive due to its high clinical significance. Herein, we synthesize crystalline MnOOH nanowires (MNWs) via a simple solvothermal treatment of KMnO4 and demonstrate that they possess excellent oxidase-like activity owing to the presence of pure Mn3+ sites on the MNWs. Particularly, MNWs catalyze the rapid oxidation of dopamine into aminochromes, which show a vivid brown color. The dopamine oxidase-like activity of MNWs follows the typical Michaelis–Mentenkinetics with excellent storage stability. Based on the affirmative catalytic features, a paper dipstick incorporating MNWs in the detection zone is constructed for the one-step colorimetric detection of target dopamine. By immersing the dipstick into the sample solution for 30 min, the sample spontaneously moves to the detection zone due to capillary force, yielding a brown color proportional to the amount of dopamine, which is quantified from an image acquired using a smartphone. With the MNW-containing solution-based assay and MNW-incorporated paper dipstick, dopamine is successfully determined with high selectivity, sensitivity, and detection precision when using spiked human serum and pharmaceutical dopamine injection samples, respectively. Successful analytical values such as the dynamic linear ranges of 3–60 μM and 0.05–7 mM are achieved with the solution-based assay and paper dipstick, respectively, along with excellent detection accuracy (95–99%) and precision (1.0–3.1%). Hence, we developed a simple and efficient nanozyme-based paper dipstick biosensor for dopamine that can be used in point-of-care testing environments.

The reliability and performance of technological equipment largely depends on timely and reliable diagnostics of less durable assembly units, which include rolling bearings. An effective tool for determining state of the mechanical rotational systems on rolling bearings is vibration diagnostics. The variety vibration diagnostic method which are used on practise is due to the complexity extracting an informative component for estimation and predicting the state of rolling bearings from the general vibration signal of the study unit. The article is dedicated information content study of narrow frequency ranges of the vibration signal operation bearing assemblies paper machines and their use as diagnostic parameters for vibration diagnostics of rolling bearings. The paper presents the analysis results of vibration diagnostics existing methods of bearing assemblies of the technological equipment and establishes the determination defects in rolling bearings by changing the vibration level on the characteristic frequencies components of the vibration spectrum and the bypass spectrum provides more specific information about the nature damage of the bearing and its operation. On the processing experimental data base i.e. the average vibration velocity spectra signal taken from the bearing assembly paper machine, we offer a relative indicator for current state bearing estimation and its state prediction progress, which helps to make a decision on the suitability or unsuitability bearing, Надійність та продуктивність роботи технологічного обладнання значною мірою залежить від вчасної і надійної діагностики найменш довговічних складальних одиниць, до яких належать підшипники кочення. Ефективним інструментом визначення стану механічних обертових систем на підшипниках кочення є вібраційна діагностика. Різноманітність методів вібродіагностики, що застосовуються на практиці, обумовлена складністю виділення інформативної складової для оцінки і прогнозування стану підшипників кочення із загального вібраційного сигналу досліджуваного вузла. Стаття присвячена дослідженню інформативності вузьких діапазонів частот вібраційного сигналу роботи підшипникових вузлів папероробних машин та їх застосуванню як діагностичних параметрів для вібродіагностики підшипників кочення. У роботі наведено результати аналізу існуючих методів вібродіагностики підшипникових вузлів технологічного обладнання та встановлено, що визначення дефектів підшипників кочення за зміною рівня вібрацій на характерних частотах складових спектра вібрації та спектра обвідної надає більш конкретну інформацію щодо характеру пошкодження підшипника та його експлуатації. На підставі обробки експериментальних даних ‒ усереднених спектрів віброшвидкості сигналу, знятого з підшипникового вузла папероробної машини, – запропоновано відносний показник оцінки поточного стану підшипника та прогнозу розвитку його стану, з визначенням якого є можливість винесення рішення про придатність чи непридатність підшипника.

The aim of this white paper is to draw attention to the roles and responsibilities of higher education and research organisations in addressing gender-based violence. These roles and responsibilities may not be recognised or are downplayed, and this results in institutions failing to take appropriate action to ensure safe environments for students and staff. Secondly, the white paper aims to explicate the essential features and elements of effective policies and actions and lastly, to highlight the critical role of institutional leadership in making the policy frameworks and actions work. This white paper is primarily intended for: institutional leaders and top management; staff responsible for the design, adoption and implementation of institutional policies; staff appointed to support victims and survivors; and any other member of the academic community committed to ending gender-based violence. It builds on the results of the UniSAFE research, including the prevalence study (Lipinsky et al. 2022, Humbert et al. 2022), the institutional policy analysis (Huck et al. 2022), case studies (Ranea-Triviño et al. 2022), interviews (Blazyte and Pilinkaite 2022), and stakeholder and expert workshops (Yellow Window 2023a, 2023b), the purpose of which have been to gain insight into and test emerging policy solutions.

In the last two decades computer-based assessment has become an important part in support of teaching and learning. It is seen as a solution to implement assessment for learning in school and provide immediate feedback on students’ performance in real-time. Research literature on computer-based assessment suggests that every measurement instrument developer before implementation of a test has to provide evidence that computer-based and paper-based versions are equivalent and provide consistent measures. There is a risk that properties of computer-based assessment including unfamiliarity with the system and proficiency level of digital skills can seriously affect students’ performance. This paper focuses on computer-based diagnostic assessment system designed to support numeracy and literacy teaching and learning. The aim of this study is to confirm that literacy and numeracy learning measurement instruments elaborated in diagnostic assessment system provide consistent results as paper-based versions of both instruments. Data were collected administering four tests. Two of the assessments were computer-based literacy and numeracy diagnostic assessments and two were paper-based versions. By analyzing both versions of assessments using various statistical techniques we explore differences in students’ performance. Our results showed that at this development phase of the computer-based diagnostic assessment system the students who completed computer-based test versions showed similar or better performance than their counterparts who completed paper-based versions.

This paper reports on the levels of fatty acids and selected sterols in effluents and nearby water bodies at Mufindi Paper Mill (MPM), southern Tanzania. Solid Phase Extraction (SPE) was used for sample extraction, and analysis was performed using Gas Chromatography-Mass Spectrometer (GC-MS). Fatty acids ranging from C11:0 to C25:0 were detected, with saturated fatty acids (SFA) being more abundant than unsaturated fatty acids (USFA). As for selected sterols, β-sitosterol and stigmastanol were more abundant than campesterol. The mean levels of SFA, USFA, β-sitosterol, stigmastanol, and campesterol (µg/L) were 538.28, 125.94, 1065.44, 1178.01, and 66.76, respectively, for untreated effluents, and 338.10, 139.03, 933.40, 153.92 and 57.82, respectively, for treated effluents. It was further established that the mean levels of SFA, USFA, β-sitosterol, stigmastanol, and campesterol (µg/L) were 321.29, 57.35, 58.37, 50.76, and 49.08, respectively, for effluents at the discharge point and 20.58, 17.72, 8.25, 10.55, and 6.05, respectively, at receiving water. Water bodies are therefore contaminated with lipophilic wood extractives since the mean concentration levels of USFA and sterols were above the lowest concentrations suspected to adversely affect fish (toxic limits (µg/L): USFA (2-8) and sterols (³10)).

In this short paper, we use a mix of scientometrics and DH methods to investigate a novel corpus of term papers from German students of the humanities, hoping to shed some light on undergrad citation practices.

Verdigris sodi med najpomembnejše in pogosto uporabljene pigmente zelene oziroma modrozelene barve od antike do 19. stoletja. Njegova barva se spreminja s časom in v odvisnosti od atmosferskih pogojev. Kljub slabi obstojnosti je bil med umetniki zelo priljubljen. Ker je semitransparenten in ne prekriva tiskarskega črnila, ga najdemo na iluminacijah, ilustracijah knjig in zemljevidih. Poznamo dve vrsti verdigrisa, in sicer nevtralni in bazični verdigris. Verdigris ne spreminja zgolj svoje barve, ampak povzroča tudi razgradnjo nosilca, na katerega je nanesen. Ker so ogrožena tudi številna zgodovinska umetniška dela, so študije stabilizacije pigmenta in razvoj konservatorsko-restavratorskih postopkov izjemnega pomena. V magistrskem delu sem raziskovala razgradnjo in možnosti za stabilizacijo različnih modelnih papirjev z nanesenim pigmentom verdigris. Študirala sem tri različne modelne papirje, in sicer Whatman No. 1 filtrirni papir kot referenčni papir in dva različna ročno izdelana papirja, ki sta podobna zgodovinskim papirjem. Vzorce papirja s pigmentom verdigris sem izpostavila pogojem termično pospešene razgradnje pri 50 °C in 65 % relativne vlažnosti, ki poteka primerljivo z razgradnjo pri sobnih pogojih. Za študije stabilizacije papirja sem uporabila dva antioksidanta, ki sta se do sedaj izkazala za najbolj učinkovita, in sicer 1(H)-benzotriazol (BTA) in tetrabutilamonijev bromid (TBABr). Z atomsko absorpcijsko spektroskopijo sem določila vsebnost bakra v modelnih vzorcih papirja in ugotovila, da lahko z uporabo ročne pršilke pripravimo vzorce z enakomernim nanosom pigmenta na papir. S spremljanjem pH vrednosti vzorcev papirja sem ugotovila, da do pretvorbe nevtralnega v bazični verdigris pride v prvem mesecu termično pospešene razgradnje. pH vrednosti papirja so pokazale, da za stabilizacijo papirja zadostuje zgolj uporaba ustreznega antioksidanta, brez dodatka alkalije oziroma sredstva za razkislinjenje. Tudi meritve spremembe barve vzorcev papirja nakazujejo na dejstvo, da se nevtralni verdigris sčasoma pretvarja v različne zelene oblike bazičnega verdigrisa. Izmed obeh antioksidantov je z vidika barvne obstojnosti takoj po nanosu najbolj učinkovit TBABr, saj so bile spremembe barve minimalne, vendar so bile po treh mesecih termično pospešene razgradnje bolj izrazite kot pri vzorcih, obdelanih z BTA. Poleg tega so na nekaterih vzorcih nastale črne pike, kar ni zaželeno. S spremljanjem stopnje polimerizacije (DP) celuloze sem ugotovila, da je najbolj učinkovit antioksidant za stabilizacijo TBABr, saj je bila razgradnja papirja, obdelanega s TBABr, po treh mesecih termično pospešene razgradnje v povprečju manjša za 33 % v primerjavi z neobdelanimi papirji. V nasprotju pa BTA ni izkazal pozitivnih učinkov na stabilizacijo papirja. Primerjava DP vrednosti, določenih z velikostno izključitveno kromatografijo in z viskozimetrijo, kaže, da bi lahko bila viskozimetrija primerna za določanje DP vrednosti za papir z verdigrisom. Meritve mehanskih lastnosti so pokazale, da pri neobdelanih vzorcih papirja po treh mesecih termično pospešene razgradnje ni prišlo do tako izrazite izgube mehanskih lastnosti, kot bi lahko pričakovali glede na določene vrednosti stopnje polimerizacije celuloze. Z ramansko spektroskopijo smo potrdili, da smo za pripravo barve uporabili nevtralni verdigris, ki se s časom spreminja v različne oblike bazičnega verdigrisa, ne glede na to, ali je papir obdelan z antioksidantom ali ne. Za stabilizacijo papirja z nanesenim pigmentom verdigris je na osnovi rezultatov najbolj primeren antioksidant TBABr, saj je bil pri zaviranju razgradnje papirja najbolj učinkovit. Poleg tega ni imel negativnega vpliva na pH vrednost papirja in ni povzročil izrazitih sprememb barve takoj po nanosu. Negativni učinek se je pokazal zgolj po treh mesecih termično pospešene razgradnje, saj so na nekaterih vzorcih pojavile črne pike. Vzrok za to je potrebno pred uporabo postopka na originalnih dokumentih natančno raziskati. Verdigris is one of the most important and frequently used green or blue-green pigments from antiquity until the 19th century. Its colour changes with time and depending on atmospheric conditions. Despite its poor durability, it was extremely popular among artists. Because it is semi-transparent and does not obscure the printed ink, it can be found on illuminations, book illustrations and maps. There are two types of Verdigris, namely neutral and basic Verdigris. Verdigris does not only change its colour, but also causes the degradation of the substrate on which it is applied. Since many historical works of art are also at risk, studies of pigment stabilization and the development of conservation-restoration procedures are of utmost importance. In my master’s thesis I investigated the degradation and possibilities for stabilization of various model papers with applied pigment Verdigris. I studied three different model papers, namely Whatman No. 1 filter paper as a reference paper and two different handmade papers that resemble historical papers. Paper samples with pigment Verdigris were exposed to conditions of thermal accelerated degradation at 50 °C and 65 % relative humidity, which are comparable to the degradation of paper with pigment Verdigris at ambient conditions. For paper stabilization studies, two antioxidants that have proven to be the most effective so far, 1(H)-benzotriazole (BTA) and tetrabutylammonium bromide (TBABr), were used. The copper content in model paper samples was determined using atomic absorption spectroscopy. The results show that an even application of the pigment on paper samples can be obtained using a spray gun. Monitoring the pH value of paper samples showed that the alteration of neutral to basic Verdigris occurs in the first month of thermal accelerated degradation. The pH values of paper indicate that for the stabilization of paper the use of an appropriate antioxidant, without the addition of alkali or deacidification agent, is sufficient. Measurements of the colour change of paper samples also indicate the fact that the neutral Verdigris eventually transforms into various forms of basic Verdigris. From the point of view of colour persistence immediately after application, TBABr is the most effective of the two antioxidants, as colour changes were minimal, but after three months of thermal accelerated degradation, the degradation was more pronounced than in samples treated with BTA. In addition, black spots appeared on some samples, which is not desirable. By monitoring the degree of polymerisation (DP) of cellulose, I found that the most suitable antioxidant for inhibiting cellulose degradation is TBABr, as the degradation of paper treated with TBABr was on average 33 % lower after three months of thermal accelerated degradation compared to untreated papers. In contrast, BTA did not show significant stabilization. Comparison of DP values, determined by size exclusion chromatography and by viscometry, indicates that viscometry may be suitable for determining DP values for Verdigris paper. Measurements of the mechanical properties showed that the untreated paper samples did not show as pronounced loss of mechanical properties after three months of thermal accelerated degradation as might be inferred from the determined values of the degree of polymerisation of cellulose. Using Raman spectroscopy, we confirmed that neutral Verdigris was used to prepare the colour, which changes over time into different forms of basic Verdigris, regardless of whether the paper is treated with an antioxidant or not. Based on the obtained results, the antioxidant TBABr is the most suitable for stabilizing paper with applied pigment Verdigris, as it was the most effective in inhibiting paper degradation. In addition, it had no negative effect on the pH value of paper and did not cause significant colour changes immediately after application. The negative effect became apparent only after three months of thermal accelerated degradation, as black dots appeared on some samples. The cause of the appearance of these black dots must be carefully studied before the treatment is used on original documents.

Oil-impregnated paper condenser transformer bushings are an important part of transformer equipment, and partial discharge (PD) occurred when defects exist on the condenser aluminum foil layers. Firstly, to study the PD process of the oil-paper insulated capacitance graded bushing with the defect of broken aluminum foil, a defective oil-paper bushing discharge sample is constructed to study the PD parameters and capacitance, and to discharge carbonization traces at different voltage levels. Then, in order to verify the process of condenser aluminum foil layer discharge and the space charge variation in the oil-paper insulation system of a sample model, the surface flashovers of a needle-plane discharge model based on the bipolar charge transport model and the hydrodynamic model was built. The simulation, by Transport of Diluted Species physics of COMSOL Multiphysics software, points out the discharge process of aluminum foil electrode caused by space charge action and electric field distortion under an electric field at different voltages. The results of simulation and sample bushing experiments showed that the PD process of the defective condenser foil layer is mainly divided into three stages: tip corona discharge, streamer in oil, and surface flashovers. The voltage amplitude is larger the more electrical branches are discharged and the shorter the discharge time is. The findings of the article have important implications for the discharge of the foil layer inside the oil-paper bushing.

Transformers play a crucial role in power systems. In this respect, fault diagnosis and aging state assessment have garnered significant attention from researchers. Herein, accelerated thermal aging and Raman scattering experiments are conducted on oil–paper insulation samples to accurately detect aging states. The samples are categorized into different aging stages based on the polymerization degree of the insulating paper. Principal component analysis (PCA), multi-dimensional scale change method (MDS), and isometric mapping algorithm (Isomap) are employed to extract features from the Raman spectra. Subsequently, the XGBoost strong classifier, optimized through Bayesian hyperparameter optimization (BO-XGBoost), is utilized to distinguish between four and ten states among 175 groups of samples after feature extraction. The subsequent classification results of the three feature-extraction methods are compared. The results indicate that Isoamp, which pertains to the manifold dimension transformation, achieves the highest average discriminative accuracy after feature extraction. The discriminative accuracies for aging states four and ten are 97.0% and 95.1% respectively, demonstrating that Raman spectroscopy manifold dimension transformation enhances the distinctiveness between samples of different aging states in the feature-extraction process. The diagnostic model constructed with Isomap and BO-XGBoost enables accurate discrimination of the aging states of oil–paper insulation.

With the growing concern for environmental protection and personal health, utilizing bio-based impregnated resin has become a sustainable approach for producing aldehyde-free decorative paper and in-house decorations. Our current work focuses on the preparation of an aldehyde-free resin (AFR) by formulating quaternized cellulose nanofibrils (QCNFs, Ave. width 10 ± 3 nm, Ave. length of and >500 nm) with aqueous acrylate emulsion. We analyzed the synthesized QCNFs, acrylate emulsion, and AFR by using various methods, including FTIR, XPS, XRD, TGA/DTG, and rheometer, to evaluate their applicability for impregnated paper processing. At a low coating weight of 4.0 g/m2, a 30.8% increase and 4.9-times increase in tensile strength and contact angle were detected, respectively. Meanwhile, the free aldehyde emission from the AFR-coated paper was found to be 0.1 mg/L even at a high coating weight of 18.8 g/m2, which is far below the E0 level requirement in the JAS 234:2003 criteria. Therefore, the surface coating of the decorative base paper was found to be competitive in covering the porous structure of the paper, reinforcing its mechanical strength, and providing high water resistance. Moreover, the lower free aldehyde emission from the AFR-coated paper ensures its safety and potential application in house decoration products.