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

Non-wood paper production, such as bamboo paper, is an alternative to meet the massive demand for paper consumption in the recent era. Bamboo paper, made from Bambusa vulgaris fibers and manufactured with the addition of activated nano-carbon, shows an improvement in paper quality. However, there is a potential worry with the incorporation of activated carbon since it may hinder the degradation process of paper. Concerning the substance's life cycle, degradation assisted by the fungal decomposer of this new product is crucial. This study investigated the effects of the white-rot fungi, viz. Phlebiopsis sp and Pycnoporus sp., on the degradation of bamboo paper with- or without- activated nano-carbon (BPAC and BPNAC). In vitro experiments that combined two variables (Fungal agents and Paper types) were carried out for 12 weeks. The results revealed that Pycnoporus sp. was more effective in decomposing both BPAC and BPNAC rather than Phlebiopsis sp. After being degraded by Phlebiopsis sp. and Pycnoporus sp. for 12 weeks, the remaining mass of BPAC was 64.14% and 48.96%, respectively, while the BPNAC was 69.89% and 38.25%, respectively. The ability of these fungal agents on composite-paper degradation was compared to other similar studies. Further investigation and possible applications were discussed.

Herein, we loaded cobalt-based zeolite imidazolate frameworks, ZIF-67 (Co), onto commercial filter paper to prepare catalytic filter paper (ZFP) for the in situ degradation of bisphenol A (BPA) in water by activating peroxymonosulfate. The results showed that ZIF-67 (Co) was densely and uniformly distributed on the surface of the filter paper. The prepared ZFP could effectively degrade BPA in situ through a gravity-driven filtration process. Specifically, when the flow rate of the BPA solution passing through ZFP was lower than 10 mL/min, 0.02 mM of BPA could be completely degraded by ZFP. Furthermore, ZFP showed promising water matrix adaptability, which could provide promising BPA degradation efficiency in a wide pH range or in the existence of multiple anions. The scavenging tests demonstrated that both sulfate radical and hydroxyl radical were generated for BPA degradation, in which hydroxyl radical was the dominant active species. The ZFP also exhibited promising long-time use stability with a high mineralization rate. This study provides a novel method to prepare high-efficient catalyst paper for the in situ organic pollutant removal in water media via a prompt filtration process. [ABSTRACT FROM AUTHOR]

Copyright of Indonesian Journal of Forestry Research is the property of Indonesian Journal of Forestry Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Once printed, books are always accompanied by the smells of volatile organic compounds (VOCs) which are continuously emitted not only by inks but also by papers themselves throughout their lives. Although the VOCs from papers may bring mild discomfort to readers, they are considered as very important factors that feature the degradation of papers and show potential applications in cultural relic appraisal. In this study, an analytical approach based on solid phase microextraction combined with gas chromatography-mass spectrometry (SPME-GC/MS) was proposed for the evaluation of volatile organic compounds (VOCs) emitted by Chinese traditional handmade papers. The VOCs evaluations and artificial aging processes were both applied to recent-made papers and naturally aged papers from a traditional Chinese calligraphy and painting scroll (collected by the National Museum of China). To be noticed, a large number of aliphatic acids, aldehydes, ketones, furan derivatives, benzene series and terpenoid substances indicated that the VOCs signals not only reveal the degradation of paper but also tentatively reflect the storage environment along hundreds of years ago. The semi-quantitative evaluation of markers indicated that the historical paper is under a serious degradation due to the high capacity it releases. Our results provided a path way to get the degradation information of ancient paintings as well as potential realistic applications such as the conservation of paper-based relics and the environmental protection in libraries and museums.

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

Aging behavior occurs in the storage process of paper archives, which accelerates the aging process of the paper. Therefore, it is important for paper archives management to explore the aging behavior of acidified paper (AP) and to delay or prevent its further aging. The aging behavior of the commonly used university archives paper with artificial acidification were studied by measuring pH value, electrical conductivity, mechanical properties and whiteness. The results show that the pH value, conductivity, mechanical properties and whiteness of AP change significantly compared with the non-acidified raw paper (P). After dry-heat aging treatment, the pH value of AP decreased more obviously than P, which shows more obvious aging degradation and further acidification of AP. During the aging process of AP, the molecular and structural degradation are promoted by the presence of acidic substances, which increase the electrical conductivity of the system. The microstructures of the paper are changed by acidification and aging treatment, and more fiber fracture, etching and microscopic holes are found in the surface SEM images. The reductions of the tensile index and whiteness of AP are also more significant because of the degradation acceleration of the acid. [ABSTRACT FROM AUTHOR]

Mineral oil has been used for many years in various electrical equipment, including transformers, as a cooling and insulation medium. However, its low biodegradability and poor performance in terms of fire protection have prompted the search for fluids to replace it, with vegetable oils being prominently considered. In this study, the dielectric, chemical, and physical properties of four vegetable oils obtained from different seeds (sunflower, rapeseed, soybean, and palm) and a biodegradable synthetic fluid are analysed throughout their lifespan in transformers. Their performances are compared with a traditional mineral oil to assess which one is more suitable for use in transformers employing this type of paper. To achieve this, the fluids were subjected to thermal ageing in combination with copper and a thermally upgraded kraft (TUK) paper, with its degradation controlled by measuring the degree of polymerisation. The results demonstrate that the origin of the vegetable oils affects their properties and degradation rates. It was found that most of the alternative fluids are suitable for use in transformers with the TUK paper and that they can increase their lifespan. [ABSTRACT FROM AUTHOR]

Herein, we loaded cobalt-based zeolite imidazolate frameworks, ZIF-67 (Co), onto commercial filter paper to prepare catalytic filter paper (ZFP) for the in situ degradation of bisphenol A (BPA) in water by activating peroxymonosulfate. The results showed that ZIF-67 (Co) was densely and uniformly distributed on the surface of the filter paper. The prepared ZFP could effectively degrade BPA in situ through a gravity-driven filtration process. Specifically, when the flow rate of the BPA solution passing through ZFP was lower than 10 mL/min, 0.02 mM of BPA could be completely degraded by ZFP. Furthermore, ZFP showed promising water matrix adaptability, which could provide promising BPA degradation efficiency in a wide pH range or in the existence of multiple anions. The scavenging tests demonstrated that both sulfate radical and hydroxyl radical were generated for BPA degradation, in which hydroxyl radical was the dominant active species. The ZFP also exhibited promising long-time use stability with a high mineralization rate. This study provides a novel method to prepare high-efficient catalyst paper for the in situ organic pollutant removal in water media via a prompt filtration process.

The reliability of power transformers operation largely depends on the insulation system condition, especially on the condition of paper insulation. Determining the condition of paper insulation of transformers in use cannot be made by direct measurements. The most common way of assessing the paper insulation condition is by analyzing the content of 2-furfural dissolved in the insulating oil and by applying correlations between the degree of paper polymerization and the 2-furfural content in the insulating oil. The concentration of 2-furfural in the oil depends on the moisture content of the insulation system and the oxygen and acid content in the oil. In order to gain a better insight into the cumulative content of 2-furfural produced by paper degradation, excluding changes in the 2-furfural content caused by migration between paper and oil at different operating temperatures, dependence of the degree of polymerization of kraft paper to 2-FAL content in the oil, corrected to a reference temperature of 20°C, for a moisture content in cellulose of 1-1.5% and 3-4% is presented in this paper. This diagram has been verified on 4 transformers according to available data from the database of the Electrical Engineering Institute Nikola Tesla. In the future, this diagram should be completed for moisture content of 2.5% in cellulose insulation.

The technique of using biochar-based catalysts in persulfate activation is a promising alternative to remov emerging and refractory pollutants (e.g., tetracycline-) in wastewater. However, the situation of biochars derived from waste pulp/paper mill sludge is still unclear. The pulp/paper mill sludge biochars (SBC300, SBC500, and SBC700) were obtained and characterized at pyrolysis temperatures of 300, 500, and 700 °C. Tetracycline degradation using peroxydisulfate activated by SBCs was investigated. The results demonstrated the removal efficiencies of tetracycline in SBC300-, SBC500- and SBC700-peroxydisulfate systems, which increased with the pyrolysis temperatures and were 4.3, 4.8, and 5.0 times that of a system with peroxydisulfate alone. The experiments of free radical quenching, singlet oxygen quenching, and electrochemistry indicated that the degradation of tetracycline in SBC-peroxydisulfate systems was mainly not a free radical pathway, but a non-radical pathway. Singlet oxygen (1O2) and electron transfer could play main roles in the degradation removal of tetracycline. The removal efficiencies of tetracycline in the SBC-peroxydisulfate systems could be up to 96.0% (SBC700-peroxydisulfate) under the optimum dosage of SBC, the molar ratio of peroxydisulfate to tetracycline and the solution pH value. The results indicate that a SBC700-peroxydisulfate system could be an effective “trash-to-treasure” treatment technique for wastewater containing antibiotics.

The development of a solid substrate for the support and stabilization of zero-valent metal nanoparticles (NPs) is the heart of the catalyst system. In the current embodiment, we have prepared solid support comprise of alginate-coated cellulose filter paper (Alg/FP) for the synthesis and stabilization of Co nanoparticles (NPs) named as Alg/FP@Co NPs. Furthermore, Alginate polymer was blended with 1 and 2 weight percent of CoNi NPs to make Alg-CoNi1/FP and Alg-CoNi2/FP, respectively. All these stabilizing matrixes were used as dip-catalyst for the degradation of azo dyes and reduction of 4-nitrophenol (4NP). The effect of initial dye concentration, amount of NaBH4, and catalyst dosage was assessed for the degradation of Congo red (CR) dye by using Alg-CoNi2/FP@Co NPs. Results indicated that the highest kapp value (3.63 × 10−1 min−1) was exhibited by Alg-CoNi2/FP@Co NPs and lowest by Alg/FP@Co NPs against the discoloration of CR dye. Furthermore, it was concluded that Alg-CoNi2/FP@Co NPs exhibited strong catalyst activity against CR, and methyl orange dye (MO) degradation as well as 4NP reduction. Antibacterial activity of the prepared composites was also investigated and the highest l activity was shown by Alg-CoNi2/FP@Co NPs, which inhibit 2.5 cm zone of bacteria compared to other catalysts.

Viscometric Degree of Polymerization (DPv or DP for short) is a well-established method used in the transformer industry to track degradation of the paper insulation used inside transformers. The DP method works well for both new, unprocessed paper, and for aged paper. But in recent years it has become an established fact that there are unclear issues related to measurements of DP on new paper after factory drying. This phenomenon has been observed for different paper types, paper dried using different drying methods, different types of pulp and measurements made at different laboratories. Cigré has recently published a reference paper on the subject [1], written by experts from different transformer manufacturers, paper manufacturers, independent laboratories and utilities. It is further noted in Cigré brochure 738 (WG D1.53) that at times, new paper after factory drying does not dissolve well in the Cuen solution used for DP measurement. This difficulty introduces tremendous uncertainties in the average DP numbers reported by laboratories for such papers. In this article we seek to shed some light on this problem and its effect on reported DP values. [ABSTRACT FROM AUTHOR]

The present contribution evaluates the methods of degradation and stabilization of alum-containing paper with a focus on the alkaline environment achieved by deacidification procedures. In terms of reviewed subjects, the contribution focuses on alum-rosin sized paper, which is still used as a carrier of knowledge and information; however, it also mentions cellulose itself and other brands of paper. The contribution summarizes the results on the homogeneity of the distribution of alum and rosin in the paper mass and on the paper surface. It provides the knowledge gained in the field of alkaline hydrolysis and oxidation with special regard to transition metal species. It shows the values of alkaline reserves achieved in the main mass-deacidification processes. On the basis of the acquired knowledge, the contribution emphasizes the procedures of paper stabilization. Criteria of “increased mechanical permanence and lifetime prolongation” adopted to evaluate and compare the efficacy of individual mass-deacidification processes were applied and corresponding data are introduced. The contribution also draws attention to the existence of open issues in the area of paper degradation and stabilization.

Old manuscripts are among the most important elements of the cultural and historical heritage of ancient knowledge. Unfortunately, many of them suffer from degradation, mostly those written with iron gall inks. In the present work, a study using non-destructive techniques was designed with the aim of analyzing the elemental composition and structural characteristics of iron gall inks, reproduced in laboratory, paper and their interaction when the ink is deposited on paper, inducing the paper degradation. Proton induced X-ray emission, X-ray diffraction and Fourier-transform infrared spectroscopy provided the elemental and structural information, and photography under infrared (IR) and ultraviolet (UV) light allowed the differentiation between manufactured inks. Results show that the first step of inked paper deterioration is due to acid-hydrolysis of the cellulose and the presence of reactive Fe(II) species by reducing the crystallinity index of the paper, which is affected depending on the ink recipe and the starting raw materials. These results will be useful to future studies on ancient documents written with iron gall inks, which suffer deterioration due to ink corrosion, and to differentiate between the different paper degradation mechanisms.

The vast majority of power transformers have an insulation system consisting of both insulating mineral oil and Kraft paper. The principal oil degradation agents are oxygen and temperature, whereas the main mechanisms of insulating Kraft paper degradation are water and acids (acidic hydrolysis degradation), temperature (pyrolytic degradation), and oxygen (oxidative degradation). [ABSTRACT FROM AUTHOR]

This mini‐review summarises and discusses recent findings form the literature on the degradation of carbon‐based electrodes for vanadium redox flow batteries (VRFBs). It becomes evident that the focus of current investigations is on carbon paper, carbon felt and graphite felt electrodes, which is understandable from a practical point of view. However, the structural complexity of these materials often prohibits doubtless attribution of observed performance reduction (or increase) to changes in the electrode materials. Among the discussed major causes for degradation are formation or change of surface functional groups, changes in the carbon sp2/sp3 ratio, intercalation of ions as well as formation of inhibiting adsorbates. In order to gain deeper insight into the changes of carbon electrodes in VRFBs under relevant operation conditions, the authors suggest reducing complexity of the investigated materials and applying in situ‐studies under well‐defined and controllable conditions on model electrodes. These studies then should be extended towards more practical systems and may finally help to reduce degradation phenomena including enhanced overvoltages and thus could improve cycling and energy efficiency as well as long‐term stability of vanadium redox flow batteries. [ABSTRACT FROM AUTHOR]

Pulp and paper mills are a major source of pollution, generating huge amounts of intensely colored effluent that goes to the receiving end of a wastewater treatment plant. The biochemical oxygen demand test (BOD5) relies heavily on the microorganism metabolic capability added to the test as seeding material. The seeding material in the testing is obtained from sewage sampling or from commercial sources. Specific organic pollutants that are present in paper and pulp mill effluent can only be degraded by specific microbes; therefore, common sewage or synthetic seed may lead to erroneous BOD5 estimations. In this study, specific microbial species were selected to evaluate their degradation efficiency, both individually and in combination. The microorganisms selected in the formulated seed exhibit BOD5 in a reproducible and synergistic manner. The formulation of this specific microbial consortium can be used to develop bioremediation strategies.

Power transformers use Kraft paper, thermally upgraded Kraft and other polymeric papers (ex. Nomex) as the main solid insulation between the winding conductors. Dielectric oil used in transformers as an insulating and cooling fluid typically has an operating temperature range of 60-90 °C. These service temperatures can cause slow degradation of both the oil and the insulating paper winding, with a loss of mechanical and dielectric properties. In this sense, this work analyzes paper degradation through Young’s Modulus, yield stress, rupture strength and strain under ultimate strength. An accelerated thermal ageing of the paper in mineral oil was carried out at temperatures of 110, 130 and 150 °C over different periods of time, in order to obtain information on the kinetics of the ageing degradation of the paper. The evolution of the mechanical properties and micro mechanisms of paper failure are analysed as a function of temperature and ageing time. Finally, the results obtained are compared with the traditional method of degradation analysis, based on the degree of polymerisation measurement. [ABSTRACT FROM AUTHOR]

The mechanical performance of two commercial papers used as solid insulation in power transformers, namely standard Kraft and a thermally upgraded Kraft paper, were studied during accelerated aging in Luminol oil at 170 ?C. The results show a relationship between the degree of polymerization and the mechanical properties measured by tensile testing. A linear relationship was found between the mechanical properties of paper, the tensile index (Tidx), and the concentration of methanol present in the oil. The methanol chemical marker has been proven to be an accurate assessment tool for the aging of cellulosic paper. The results show a promising tool for correlating the methanol concentration in oil, as an indirect indicator, with the mechanical performance of the paper. This approach can be used to monitor the real state of the cellulose chains in the power transformer insulation paper. [ABSTRACT FROM AUTHOR]

Cellulose destruction reactions consist of a series of physico-chemical phenomena, which cause the shortening of macromolecular chains. [...]

Vegetal oils are considered a suitable substitute for mineral oil that is widely used in power transformers as insulation and cooling medium. Due to the fact that more and more power transformers containing this alternative insulating fluid are being constructed a mathematical ageing models is needed to help predict transformer failures. The continued performance of power transformers depends on the condition of its paper insulation mainly. In this sense, this paper analyses Kraft paper degradation through the loss of its mechanical strength. Accelerated thermal ageing test of the paper in two different vegetal oils were carried out at three temperatures during diverse periods of time, in order to obtain information on the kinetics of the ageing degradation of the paper. The evolution of the mechanical properties of paper failure are analysed as a function of temperature and ageing time. In addition, the results obtained are compared with the traditional method of degradation analysis, based on the measurement of the degree of polymerisation. [ABSTRACT FROM AUTHOR]

The technique of using biochar-based catalysts in persulfate activation is a promising alternative to remov emerging and refractory pollutants (e.g., tetracycline-) in wastewater. However, the situation of biochars derived from waste pulp/paper mill sludge is still unclear. The pulp/paper mill sludge biochars (SBC300, SBC500, and SBC700) were obtained and characterized at pyrolysis temperatures of 300, 500, and 700 °C. Tetracycline degradation using peroxydisulfate activated by SBCs was investigated. The results demonstrated the removal efficiencies of tetracycline in SBC300-, SBC500- and SBC700-peroxydisulfate systems, which increased with the pyrolysis temperatures and were 4.3, 4.8, and 5.0 times that of a system with peroxydisulfate alone. The experiments of free radical quenching, singlet oxygen quenching, and electrochemistry indicated that the degradation of tetracycline in SBC-peroxydisulfate systems was mainly not a free radical pathway, but a non-radical pathway. Singlet oxygen (1O2) and electron transfer could play main roles in the degradation removal of tetracycline. The removal efficiencies of tetracycline in the SBC-peroxydisulfate systems could be up to 96.0% (SBC700-peroxydisulfate) under the optimum dosage of SBC, the molar ratio of peroxydisulfate to tetracycline and the solution pH value. The results indicate that a SBC700-peroxydisulfate system could be an effective "trash-to-treasure" treatment technique for wastewater containing antibiotics. [ABSTRACT FROM AUTHOR]

The transformer is a core device of the power system, and it is generally considered that the aging of insulating paper is important to the transformer. The aging process of insulating paper is the degradation process of cellulose. If it can be detected regularly, the aging of oil–paper insulating systems can be monitored conveniently. 5‐hydroxymethylfurfural is an important chemical substance produced by cellulose decomposition. It has broad prospects because of its many advantages. The oil–paper insulation system was thermally aged at 80, 90, 100, and 110 °C to measure the concentration of 5‐hydroxymethylfurfural on insulating paper and in transformer oil. In this paper, the concentration of 5‐hydroxymethylfurfural is detected by high‐performance liquid chromatography. The linear correlation coefficient of this method can reach 0.99, and the minimum detected concentration can be reduced to 10 µg/l. Experiments show that the concentration of 5‐hydroxymethylfurfural increases with the aging time, and when degree of polymerization (DP) decreased, the concentration of 5‐hydroxymethylfurfural increased. The correlation coefficient is greater than 0.92, which shows that there is an experimental relationship between the concentration of 5‐hydroxymethylfurfural and DP. The parameters of regression curves are different at different temperatures, but in actual operation, the temperature is low and remains stable. Therefore, 5‐hydroxymethylfurfural is expected to be a new indicator of the aging degree of oil–paper insulation system. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Bubbles, as typical defects of oil–paper insulation systems, pose a great threat to the insulation state. In this article, the characteristics and mechanisms of the partial discharge (PD) inception, evolution, and induced breakdown of bubbles embedded between oil-impregnated paper (OIP) layers are investigated. The results show that the PD inception has a significant statistical time delay due to the lack of free electrons. The PD inception time delay (PDTD) follows an exponential distribution and leads to the large dispersion of the PD inception voltage (PDIV), which follows a Weibull distribution. The changes in PD behavior [charge, repetition rate, pulse current waveform, and phase-resolved PD (PRPD)] over time all show two separable stages (stages 1 and 2). The continuous recording of bubble area and gas composition under PD reveals that the evolution of bubble PD is attributed to the change in gas composition rather than the change in surface conditions as believed by researchers. The OIP breakdown induced by bubble PD indicates two breakdown modes, fast and slow, which correspond to direct-induced breakdown in stage 1 and cumulative-damage breakdown in stage 2. The former occurs because of the severe distortion of the electric field by the space charge at the head of the discharge channel inside the bubble, whereas the latter occurs because of the gradual deterioration of the OIP due to the continuous PD action. This study increases our understanding of the mechanisms of bubble discharge and of oil–paper insulation deterioration, and it provides guidance for fault diagnoses. [ABSTRACT FROM AUTHOR]

The ecological environment is increasingly damaged due to the impact of mineral oil extraction and leakage. As a kind of sustainable resource, a vegetable oil transformer has bright application prospects in future. However, the stability of vegetable oil has always been a problem to be solved. In addition, the metallic copper inside the transformer has a certain catalytic effect on the deterioration of vegetable oil. In this article, a copper–oil–paper insulation model is established. Based on the molecular dynamics simulation method, the catalytic mechanism of copper on the deterioration of oil-paper insulation is revealed from the microscopic level. Then, the effects of temperature, contact area, and oxygen on the catalytic effect of copper are discussed. The results show that copper could accelerate the decomposition of oil-paper insulation by attracting H atoms and O atoms in oil-paper. The increase in temperature accelerates the progress of the catalytic reaction and aggravates the deterioration of oil-paper insulation. The oxygen concentration has an important influence on the catalytic reaction of copper. As the oxygen concentration increases, the catalytic effect of copper is weakened. The abovementioned research could provide some theoretical reference for further exploration of effective oil-paper insulation deterioration protection technology. [ABSTRACT FROM AUTHOR]

Copyright of Acta Musei Brukenthal is the property of Brukenthal National Museum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Restaurator is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Utilities need to understand the aging of paper insulation in order to prolong the life of transformers. If the paper becomes severely degraded, it loses its mechanical strength and thus its ability to insulate the windings. [ABSTRACT FROM PUBLISHER]

As sugar is an important intermediate in the early stage in the degradation of cellulose, this paper proposes to use the concentration of total sugar as an indicator of the degree of aging of insulating paper in an oil-paper insulation system. The oil-paper insulation system was simulated at 90, 100 and 110°C, and total sugar concentration in insulating paper and in transformer oil was measured by spectroscopy. The spectrum of sugar reaction was obtained by spectrometer, and TQ Analyst software was used to process the data. Our experiments have shown that the total sugar concentration increases significantly in the early stage of aging, and there is a linear relationship between the logarithm of total sugar concentration and the degree of polymerization. We obtained the relationship between absorbance and total sugar concentration using the partial least square method and the regression goodness of fit is better than 0.91. [ABSTRACT FROM AUTHOR]

Cellulose material is a dielectric with intricate microscopic relaxation processes due to its complex structure. However, conventional models and curve fitting methods used for tracing and analyzing these processes often fail to capture crucial dielectric information. This paper aimed to extract the Distribution of Relaxation Time (DRT), the most fundamental and effective dielectric information providing the time scale and relative contribution of all microscopic relaxation processes. First, a distributed extended Debye model with infinite branches was constructed based on the microscopic nature of dielectric relaxation. Then, an implicit equation of the DRT function was established, inspired by the mathematical principles of infinite subdivision and summation. To obtain the numeral solution of the DRT function, a regularization method was proposed and validated. Finally, the approach was applied to cellulose insulating paper with varying degradation degrees. The relaxation process with a long time constant played a significant role, and variations during the degradation process were attributed to reduced activation energy. With clear physical interpretation and robust mathematical foundation, our method sheds light on the intricate dielectric relaxation processes in cellulose. This not only enhances the theoretical understanding and practical application of cellulose materials but also provides valuable insights for the analysis and application of other materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Chemija is the property of Lithuanian Academy of Sciences Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pulp and paper mills are a major source of pollution, generating huge amounts of intensely colored effluent that goes to the receiving end of a wastewater treatment plant. The biochemical oxygen demand test (BOD5) relies heavily on the microorganism metabolic capability added to the test as seeding material. The seeding material in the testing is obtained from sewage sampling or from commercial sources. Specific organic pollutants that are present in paper and pulp mill effluent can only be degraded by specific microbes; therefore, common sewage or synthetic seed may lead to erroneous BOD5 estimations. In this study, specific microbial species were selected to evaluate their degradation efficiency, both individually and in combination. The microorganisms selected in the formulated seed exhibit BOD5 in a reproducible and synergistic manner. The formulation of this specific microbial consortium can be used to develop bioremediation strategies. [ABSTRACT FROM AUTHOR]

The compatibility of a newly developed ester fluid (PKOAE) with cellulose insulation paper is evaluated by performing thermal ageing of Kraft paper in the new ester fluid. Thermally accelerated ageing was performed in sealed mild steel pressure vessel containing ageing catalysts, thermally upgraded insulation paper, and dielectric fluid (mineral oil and palm kernel oil alkyl ester) at 150°C for 28, 56, and 84 days. Under the same illumination, the color level of ester aged paper samples decreased by 33% after 84 days of ageing as compared with the color level of aged mineral oil impregnated paper samples which decreased by 73% within the same time. Whilst the samples of PKOAE impregnated paper exhibited approximately 5% reduction in tensile strength after 28 days of ageing, the kraft paper samples closer to copper strips were found to have a significant faster degradation rate. The tensile strength of paper samples closer to copper plates dropped to about 35% of the tensile strength of the unaged sample after ageing for 28 days, and the paper layers farther away from the copper plates decreased by about 10%. The mechanisms that could be responsible for the slower ageing rate of kraft paper in PKOAE fluid are discussed. The characteristic breakdown strength of PKOAE impregnated paper is on the average, 42% better than mineral oil impregnated paper. The high breakdown strength of PKOAE fluid may be responsible for the higher breakdown field of ester-paper system since the applied electrical stress is shared by the oil-paper combination. [ABSTRACT FROM AUTHOR]

Measurement of transformer remaining useful life has long been a goal for responsible asset management. Most testing laboratories offer furan concentration testing as a suitable method. The interpretive method of choice is usually the Chendong equation, expressed in practical terms as degree of polymerization of the paper with new paper at about 1000 and end of life at around 300. Typical mill transformers have thermal insulation ratings expressed as 55 °C rise for plain kraft or 65 °C, which corresponds to thermally upgraded kraft paper (TUP). It has been determined that TUP does not produce furans and, thus, provides a false indicator of the cellulose breakdown. There are several recent papers that have demonstrated that a measurement of methanol (MeOH) may be a better method to determine ageing of the TUP insulation and also better for transformers with plain kraft paper insulation. The objective of this paper is to provide an overview of the reasons why furans should not be used as the basis for measuring aging of thermally upgraded paper, why MeOH should be so used, and to compare actual furans and MeOH test data for service aged transformers in a process industry application [ABSTRACT FROM AUTHOR]

During the building operation phase, it is recognized that the performance of building envelope elements and energy supply systems drops with time. This performance degradation usually leads to lower energy efficiency and higher life cycle costs than predicted in the early design phase. This paper quantitatively reviews the impacts of this deterioration on the whole building performance. From the findings of the reviewed literature, it can be concluded that the whole building performance is very sensitive to several deterioration factors, particularly the performance degradation of the heating, ventilation and air conditioning (HVAC) system. The impact on the whole building performance mostly ranges from 20% to 30% over 20 years, according to the reviewed studies. [ABSTRACT FROM AUTHOR]

Capillary zone electrophoresis was used for a comprehensive characterisation of several classes of degradation products from old books. Using different methods with direct and indirect UV detection, three categories of organic compounds were investigated, namely low-molar mass organic acids, aromatic lignin derivatives, and simple carbohydrates. The occurrence of these compounds in paper depended on the state of degradation and on the type of pulp. Formic, acetic, glycolic, succinic, and lactic acids originated from holocellulose degradation. In lignocellulosic papers, acetosyringone, 4-hydroxyacetophenone, 4-hydroxybenzaldehyde, vanillin, vanillic acid, furoic acid, and 4-hydroxybenzoic acid were attributable to the lignin fraction. These two classes of compounds could be analysed directly from the aqueous extracts of papers. Glucose and cellooligomers formed through cleavage of the cellulose chain, while the hydrolysis of hemicelluloses yielded mainly pentoses among which arabinose and xylose were the most abundant. The carbohydrates were derivatised with 4-aminobenzoic acid ethyl ester prior to analysis. All the organic compounds identified were found in a panel of papers from various origin (rag, kraft, and groundwood pulps) and diverse states of deterioration, whether naturally or artificially aged. The production of these compounds was followed during the accelerated ageing of the papers and an attempt to pointing to possible molecular indicators of paper degradation was made. [Copyright &y& Elsevier]