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ABSTRACTVolatile organic compounds (VOCs) generated from naturally aged Japanese hanging scrolls and their model samples were measured using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) to clarify the effect of different painting papers and raw materials on the degradation state of hanging scrolls. VOC-based degradation markers were identified and their applicability was considered for degradation evaluations of actual Japanese hanging scrolls. The relative peak areas of different VOC groups were calculated by normalising their peak areas to the total peak area of long-chain hydrocarbons. When a painting paper was immersed in a CuSO4・5H2O solution, or coated with an alum solution, the relative peak areas of furfural and carboxylic acids increased after accelerated ageing, while these relative peak areas decreased when animal glue was applied, indicating that animal glue inhibited the generation of VOCs. When the painting paper containing Cu2+was stacked with lining paper, furfural and carboxylic acids migrated into the lining paper with ageing. Animal glue coated on the painting paper retarded this migration into the lining paper. For the lining paper coated with wheat starch paste, the relative peak areas of furfural, carboxylic acids, and aliphatic aldehydes did not change significantly with ageing, indicating that wheat starch paste did not contribute to paper degradation, although these relative peak areas increased when aged wheat starch paste was applied. These results indicate that the targeted VOCs are valid degradation markers of Japanese hanging scrolls.

ABSTRACTTo understand the degradation behaviour of rolled hanging scrolls for future conservation treatments, we evaluated the degradation–position profiles of naturally aged hanging scrolls and their model samples, which were subjected to different storage conditions. For the sample immersed in a CuSO4・5H2O solution and rolled around a glass rod, accelerated ageing using the open method (80°C, 65% RH) revealed a tendency of lower pH and higher discolouration towards the central positions, where rolling caused the most tightness. However, no clear tendencies were observed for the concentration variations of organic acids. The degradation effects of the organic acids emitted from the paulownia wooden box were also examined using the sealed tube method by enclosing the rolled painting paper and acidic paper containing organic acids together in a glass tube. Large amounts of oxalic and formic acids were detected at the periphery and scant migration of the organic acids was observed towards the centre, thus indicating that the central positions of the painting paper were less susceptible to the influence of the organic acids emitted from the external environment. By contrast, glycolic acid diffused towards the centre. The analysis of two naturally aged hanging scrolls showed different degradation behaviours. One sample, stored open in the rolled state, showed severe discolouration with the naked eye at the outermost back surface of the scroll. This was possibly associated with the large amount of sulfate ions originating from the external atmosphere, which kept the pH lower and increased discolouration towards the peripheral positions of the painting paper. For the sample stored in a paulownia wooden box, discolouration was not observed with the naked eye at the outermost back surface of the scroll, although lower pH and higher discolouration were observed towards the central positions.

ABSTRACTOne of the factors affecting the life expectancy of hanging scrolls is the storage environment. Our study focused on clarifying the degradation behaviour of painting paper, concentrating on the specific storage conditions that provide an airtight environment in a storage box and the stacked structure of the rolled paper rather than considering the materials of the wooden storage box or the gases generated from it. The degradation behaviour and rates for the sealed tube and moist heat ageing methods, excluding the additional effects of light and air pollutants, were compared. When the painting paper was immersed in a CuSO4・5H2O solution instead of a copper green pigment, the oxidation of the painting paper, attributed to Cu2+, proceeded faster with the sealed tube method than with the moist heat method. The co-occurring organic acids generated, namely glycolic and formic acids, which were secondary components, were detected in a higher amount in the first lining paper than the painting paper. This implies that the acids migrated from the painting paper into the lining paper. However, oxalic acid, which was the main component, did not significantly migrate and remained in the reaction system in the sealed tube without volatilising. This increased the hydrogen ion concentration in the painting paper and accelerated acid hydrolysis. Consequently, discolouration and a decrease in the degree of polymerisation and physical strength proceeded faster with the sealed tube method than with the moist heat method. Thus, although this result does not necessarily invalidate the storage system of a rolled hanging scroll in a box, the storage of a deteriorated hanging scroll in a closed system is expected to degrade the painting paper faster than it would in an open system.

ABSTRACTA Japanese painting paper is sized with an aqueous solution of alum and animal glue followed by brushing with a mixture of pigments of various colours and aqueous animal glue solution. Subsequently, to mount the Japanese painting to a hanging scroll, the backside of the painting is lined with a first lining paper using wheat starch paste for mechanical support. To evaluate the permanence of the painting paper as a composite material in the hanging scroll, the deterioration behaviour of the unlined painting paper and the lined painting paper was compared considering the material dynamics. After moist heat accelerated ageing (80°C, 65% RH), in the sample immersed in a CuSO4・5H2O solution, cellulose was oxidised by Cu2+to generate organic acids in the painting paper, and Cu2+and organic acids migrated to the lining paper. Consequently, the discolouration and oxidation of the painting paper in the lined complex were relatively low compared with those of the unlined painting paper. The pH decrease in the painting paper was also small in the lined complex. Moreover, if the animal glue solution was coated on the painting paper, a buffer effect was shown to operate against the organic acids derived from the oxidation of Cu2+, thereby inhibiting the migration of Cu2+into the lining paper. In conclusion, the presence of the lining paper inhibited the decrease in the physical strength and degree of polymerisation of the cellulose in the painting paper, thus contributing to its permanence in the lined hanging scroll.

Traditional papermaking was a significant innovation that intrigued the information-sharing society in a wide range of the globe. The importance of finding the historical background hidden behind the historical traditional paper is critical to understanding societies in history. Advanced molecular biological research is applied to many forensic studies to identify the origin and criminal events. Yet, biological research refrained from the heritage science of traditional papers due to its damage to the samples. The current study explores the Pearson correlation between DNA in traditional paper and non-destructive measurement of characteristics of traditional paper. DNA concentration and purity were found to have a proportional relationship based on the CIEL*a*b*color system. The color of the traditional paper was assessed assessment shows green and yellow rather than red and blue. The DNA concentration demonstrated a positive linear correlation with the peaks of 992 cm−1, 1599 cm−1, and 1628 to 1638 cm−1region, which were lignin-specific functional groups. The presence of lignin in traditional paper defines the colors green and yellow, which is related to the presence of a cell wall. The quantity of cell walls present is linked to DNA survival during the traditional papermaking process. Furthermore, the partial least square (PLS) regression model is established. The prediction model based on DNA, paper properties, and smoothing + the second derivative preprocessed attenuated total reflection-Fourier-transform infrared (ATR-FTIR) spectral data demonstrated valid purity predictions. The evaluation parameter of the cross-validated prediction model contains a low Root Mean Square Error of Cross-Validation (RMSECV) of 0.091 for DNA purity. The determination coefficient was close to 1. However, the further establishment of a validated DNA extraction methodology is required for the consistency of the prediction model for DNA concentration. The hierarchical clustering analysis demonstrated the agglomerative dendrogram on traditional paper samples. For the dendrogram, the Nasu paper mulberry (originating in northern Japan) was distinguished from another paper mulberry (originating in southwestern Japan) by clustering. By multivariate statistical analysis, the DNA presence and quality were predictable from the Japanese traditional papers. In addition, the clustering analysis provided the possible origin of paper mulberry materials for traditional papers. Based on the preliminary information, the need for DNA analysis on historical traditional paper can be determined.

Paper is a material with a high Young’s modulus that vibrates sensitively due to environmental noise, voice, and sound. This study aims to create a triboelectric power generator to convert this sonic vibration energy into electrical energy to power microelectronics embedded on paper. A sonic wave has two wave modes, transverse and longitudinal, that propagate in paper; therefore, two types of triboelectric power generators were designed for trial simulation as the first step. A triboelectrically charged polytetrafluoroethylene sheet and a back electrode were attached to a paperboard. Another paperboard with a counter electrode attached was vibrated in the out-of-plane direction corresponding to transverse waves such that it would repeatedly move toward and away from the other paperboard. The generated power between the two electrodes reached 11.8 µW at 2 MΩ load. When comb-shaped electrodes were applied, manual strokes in the in-plane direction, corresponding to a longitudinal wave, induced voltage up to 8.2 V. The result suggested that sonic waves could be an electric power source for microelectronics in the future.

It is challenging to purify oily wastewater, which affects water-energy-food production. One promising method is membrane-based separation. This paper reviews the current research trend of applying cellulose as a membrane material that mimics one of three typical biostructures: superhydrophobic, underwater superoleophobic, and Janus surfaces. Nature has provided efficient and effective structures through the evolutionary process. This has inspired many researchers to create technologies that mimic nature’s structures or the fabrication process. Lotus leaves, fish scales, and Namib beetles are three representative structures with distinct functional and surface properties: superhydrophobic, underwater superoleophobic, and Janus surfaces. The characteristics of these structures have been widely studied and applied to membrane materials to improve their performance. One attractive membrane material is cellulose, whichhas been studied from the perspective of its biodegradability and sustainability. In this review, the principles, mechanisms, fabrication processes, and membrane performances are summarized and compared. The theory of wettability is also described to build a comprehensive understanding of the concept. Finally, future outlook is discussed to challenge the gap between laboratory and industrial applications.

Coated paper-to-coated paper friction properties were examined in relation to printing runnability difficulties like erroneous double feeding of paper sheets. Higher ratios of precipitated calcium carbonate (PCC) to clay in mixed pigment coatings resulted in higher static and kinetic coefficients of friction (COFs). Microroughness in the order of pigment particle size is considered to relate to COF, because cube-shaped particles of PCC resist sliding. Calendering decreased COF at larger amounts of PCC, but did not change COF of the sole clay formulation at all. Addition of ground calcium carbonate (GCC) decreased COF. The rate of decrease in kinetic COF with increasing number of sliding for the GCC-rich formulation was higher than that for the PCC-rich formulation, presumably because protruding parts, characteristic of the GCC-rich formulation, on the surface were selectively flattened. Addition of styrene-butadiene (SB)-latex up to 14pph decreased COF, but static COF had the highest value at 18pph. The antislip property (as a rubber) of SB-latex developed only in the static mode. Among lubricants formulated, the wax type decreased COF the most remarkably with more effect on kinetic COF than on static COF.

In this work, we evaluated the feasibility of a paper-based bacterial detection system. The paper served as a substrate for the measurement electrodes and the culture medium. Using a printing technique, we patterned gold electrodes onto the paper substrate and applied Luria broth (LB) agar gel as a culture medium on top of the electrodes. As the first step towards the development of a bacterial detection system, we determined changes in the surface potential during bacterial growth and monitored these changes over 24 h. This allowed us to correlate changes in the surface potential with the different growth phases of the bacteria.