Search

Paper cultural relics such as double-sided printed newspapers and periodicals represent modern cultural heritage. Severe damage such as embrittlement, decay, and dreg generally occur to paper; hence, it urgently needs conservation and restoration. Therefore, herein, a new reinforcement method for the fragile double-sided printed paper cultural relics is proposed with cotton mesh and adhesive PVA217 as reinforcement materials. Using a computer measured and controlled folding endurance tester, a pendulum tensile strength tester, pH meter, pulp viscosimeter, and other instruments, the physical properties of newspaper samples before and after aging were evaluated. In addition, the mechanical properties, chromatic aberration and surface morphology of simulated samples before and after the cotton mesh reinforcement and Japanese washi paper reinforcement were assessed. The experimental results indicate that this new reinforcement method could effectively improve the physical strength, chromatic aberration and durability of the simulated samples. Widespread applications of this cotton mesh reinforcement method for the reinforcement and protection of the red revolutionary cultural relics such as double-sided printed newspaper and periodicals during the Republic of China era are foreseeable.

Perforation is used in multilayer tissue products, such as toilet and kitchen papers, as part of the converting process. Perforation facilitates the detachment of consecutive sheets by the user. The compromise between the strength required to detach a perforated sheet and the strength required to break a sheet affects the perforation efficiency. In this work, the mechanical behaviors of 15 commercial papers from different European producers were studied. A morphological analysis of the materials was performed, followed by the determination of their perforation efficiency (through tensile tests). A qualitative analysis of the cuts quality, along with a quantitative analysis of the same cuts dimensions was performed through an optical system. Finally, the stress concentration in the holes and the influence of the cuts distance were analyzed using a finite element model implemented in Abaqus/Standard finite element software. The results showed that a cut distance of 2.0 mm should not be used in these types of papers, and the perforation efficiency increased with the cut distance, regardless of the number of plies in the toilet paper. The stress concentration factor was also determined to have a limit value of 0.11. Papers above this limit value tear at the perforation line, as desired.

Our dependency towards wood has reduced the number of forests especially in Indonesia. Hence, many people tried to use another material as a replacement of wood. One of them is composite. Department of Industrial Engineering Universitas Sebelas Maret has developed paper-based composite using newspaper waste in Praktikum Perancangan Teknik Industri (PPTI) II. Unfortunately, the quality of composite is not so good. This paper tried to understand the effect of factors to responses and discover the best combination of factors to obtain the best responses. The responses of this experiment are tensile strength, bending strength and impact value. The factors of this experiment are paper pulp, PVAc glue and water. Taguchi method is used to find the appropriate orthogonal array and Particle Swarm Optimization method to find the optimum combination of the factors. Orthogonal array used in this experiment is L9 (34). Through analysis, all of the factors are significant to tensile and bending strength, but they are not significant to impact value. The best combination of factors is 175 grams paper pulp, 130 grams PVAc glue and 175 ml water. Optimum results obtained for tensile strength is 0.7595 N/mm2, bending strength is 4.873 N/mm2 and impact value is 0.0138 J/mm2.

Traction transformers are one of the most important equipment in the traction power supply system. Thermal aging of transformer insulation system determines its reliable life. To achieve an estimation of the insulation life of traction power transformers operated under real load condition, the effects of traction loads on the thermal aging of oil-paper insulation in traction transformers were investigated. First, the design principles for the accelerated thermal aging experiment were studied and proposed by considering magnitude (i.e., load rate) and frequency (i.e. spare time and lasting time) of the traction load. Then, an experimental system was established in the laboratory to conduct extensive accelerated thermal aging experiments, in which the traction loads were mimicked by using positive temperature coefficient (PTC) heating plates and a programmable logic controller (PLC). Finally, the experimental results were analyzed and discussed to reveal the effects of traction load on the thermal aging of oil-paper insulation in traction transformers.

During the cold season, the cold protective products are often short during evacuation life after a natural disaster. If evacuees can make and wear simple cold protective gears by using materials obtainable on site, it will reduce the burden on the evacuees in emergent situation. Therefore, we investigated the structure constructed by folding newsprint paper, which can improve the heat retention effect and be applied to various body shapes. Focusing on the glide reflection structure repeating a smaller chamber, the basic size was determined by experiments with reference to the accordion shape, and the experimental results indicated that the heat retention effect was significantly greater than that of a mere air layer and those of ordinary fabrics. Next, it was found that the apex angle of structure had no significant difference in the heat retention effect. Then, the dimensions of the structure were determined to maintain the air layer under the pressure of the clothes by simulation of structural analyses. Finally, we made a temporary cold protective gear that can practically cover the trunk of the body and found that the heat retention effect was significantly higher than that of unprocessed newsprint and that of accordion shape.

In present investigation, an attempt was made to optimise the peak stress for paper laminate composite using FRANC2D software. It was observed that the laminate having the triangular geometry supposed to be most appropriate as it has the lowest value of peak stress contour compared to other models like parallel strip, up-down tapered and down-up tapered. The minimum peak stress was observed for the samples having triangular geometry while the maximum was observed for down-up tapered samples. Therefore, the hypothesis adopted to use in-built materials with variables reinforcement area and strip geometry and length in the FRANC2D software to optimize the sample geometry and then apply it to the paper laminate by considering its mechanical properties might be use to optimize the peak stress of paper laminate composite in tensile loading conditions. It was also observed a length of one-quarter of the length of the plane strip, might be the optimum length of the paper laminate samples. However, it feels that, the above model can be further modified considering a more significant mechanical properties as well as different sample geometries.

En el context d’emergència climàtica en que ens trobem, l’arquitectura ha d’aportar solucions en relació als seus mètodes de disseny i processos constructius, per tal de reduir les emissions de CO2 i el consum d’energia que se’n deriva. Els mètodes de Form Finding ens permeten crear la forma òptima d’una estructura, optimitzant l’ús de materials i economitzant el procés constructiu. Un tipus d’estructura resultant d’aquests processos són les funicular shells, geometries que treballen exclusivament a compressió i que permeten l’ús de materials més sostenibles. Tot i així, aquest tipus d’estructures han esta poc implementades tradicionalment per la complexitat dels seus processos de disseny i construcció. A l’actualitat, les eines de disseny i fabricació digital han obert noves portes per a la implementació eficient, viable i econòmica de les funicular shells. En aquest treball s’analitzaran els avenços que ha suposat les eines computacionals en el disseny, construcció i aplicacions d’aquestes estructures, valorant si han representat un canvi de paradigma en la seva implementació i explorant les seves capacitats per esdevenir una alternativa sostenible per a la arquitectura del futur. In the context of climate emergencyi, architecture must provide solutions in relation to its design methods and construction processes, in order to reduce CO2 emissions and the energy consumption derived from them. Form Finding methods allow us to create the optimal shape of a structure, optimizing the use of materials and lowering the costs of the construction process. One type of structure resulting from these processes are funicular shells, geometries that work exclusively in compression and allow the use of more sustainable materials. However, these types of structures have traditionally been poorly implemented due to the complexity of their design and construction processes. Nowadays, digital design and manufacturing tools have opened new possibilities for the efficient, viable and economical implementation of funicular shells. This work will analyze the advances made by computer tools in the design, construction and applications of these structures, assessing whether they have represented a paradigm shift in their implementation and exploring their capabilities to become a sustainable alternative for the architecture of the future.

Life expectancy of power transformers is limited by the integrity of insulating cellulosic paper wound around transformer winding. The insulating paper is subjected to thermal, electrical and mechanical stresses. There are three main factors causing degradation in the paper, i.e. moisture, oxygen and temperature. In this work, the degradation rate due to temperature is only discussed. That means that transformer life could be shortened or extended by adjusting loads which results in higher or lower temperature conditions. The temperature, namely the hot-spot temperature is typically used to estimate the relative ageing rate and loss of insulation life. Being able to estimate the hot-spot temperature accurately given load and weather data helps operators to plan about transformer replacement properly. This could also reduce costs of early replacement due to a conservative estimation. In this work, thermal models have been developed using machine learning techniques to learn thermal behavior from historical data. The data are comprised of the hot-spot temperature estimated by winding temperature indicator (WTI), load profiles, ambient temperature, rainfall, wind speed and direction and solar radiation. The proposed method has been validated using data for five 400kV/275kV, four 400kV/132kV and two 275kV/66kV autotransformers and has been shown to work effectively.

Tight assembly of stator windings with no insulation paper damage is a manufacturing challenge. We evaluate different sets of parts according to the following parameters: magnet wire thickness, stator slot smoothness, length of the straight magnet wire after the slot end, and type and amount of insulation cap at the end of the slot. These parameters have discrete values with small differences between them. The damage criterion is the decrease of the insulation paper breakdown voltage after assembly/disassembly of parts, assembled in a small set of designed experiments. Parameter values, i.e., levels at individual experiments are set by an orthogonal experiment matrix. Repetition of each experiment provides statistical significance. Data analysis shows that the additive model alone is not sufficient due to the high correlation of the parameters’ influences. We extend the model to include interparameter influences, which we model by adding a virtual parameter. The extended additive model generates parameter values that do not degrade the insulation paper breakdown voltage within the manufacturing process. These values are verified by repetitions of the control experiment.

The need for facilitation of access to soil information has never been greater. Growing human population, shrinking land and water resources, soil pollution, climate change and unequal distribution of agriculture-oriented technology impact negatively on global food security. There has been a long-standing interest in developing low-cost and easily accessible soil field kits to measure different properties of agricultural soils in order to improve their agronomic capacity. Test strips, in particular, have provided a favoured method of obtaining soil nutrient status information since the 1970s. Today there is renewed interest in using semi-qualitative colorimetric methods in soil assessment due to incorporation of modern technological solutions, such as smartphones, which could in turn increase the accuracy and precision of the existing methods. In this paper, we propose streamlined testing procedures based on experience gathered that may be conducted prior to a field kit development involving test strips. Results from laboratory and field experiments are presented, highlighting important factors which ought to be taken into account at the commencement of test-strip oriented studies.

Traction transformers have been withstood the effects of shock load, which would become more than 2~3 times rated load when the train passes, and it can result in the winding insulation under short-term high temperature frequently. And the average load far less than 50% result in relatively low oil temperature, the very uneven rise of temperature lead to the very uneven distribution of insulation aging. In order to evaluate the aging life of oil-paper insulation of traction transformer under shock load effectively, in this paper, Ekenstam aging kinetic model was optimized considering the effect of shock temperature, shock duration and shock interval on cellulose degradation rate of insulating paper. Firstly, the effects of shock temperature, shock duration and shock interval on the parameters of Ekenstam model are analyzed and determined by handing and testing experimental materials. Then, according to the test data, the Ekenstam optimization model considering shock temperature, shock duration and shock interval is obtained. Finally, the optimized model is verified by experiments. The results show that the optimization model can effectively evaluate the aging life of oil-paper insulation of traction transformer under shock load in the temperature range, which provides a basis and reference for the subsequent related research.

The threat of increased industrial accidents and extreme explosive activities demands protection of structure against blast loading. The pressure-impulse (P-I) diagrams also called iso-damage diagrams indicates damage level in a structure. In the present investigation, P-I diagrams for sandwich panel with steel face and back-sheets and paper honeycomb core are developed. The numerical approach is used to get series of pressure and impulse points for particular damage level. The damage criteria considered in present study is maximum back sheet deflection. However, core crushing is limited to 5 mm in this investigation for the uniformity of the analysis. Sandwich panel with paper honeycomb core is modelled in ABAQUS/Explicit® and blast load is applied for range of loading i.e. impulsive, dynamic and quasi-static using CONWEP formulation. Based on the analysis performed, P-I diagrams are developed for damage levels of 1%, 1.5%, 2%, 2.5% and 3%.

Condenser bushings are considered the Achilles’ heel of power transformers because most of the explosions of transformers relate to their bushings’ failure. Typical bushings monitoring methods measure the tan delta, power factor, and bushings’ capacitance in line frequency. In contrast, the dielectric frequency response (DFR) or the frequency domain spectroscopy (FDS) measures these parameters over a wide frequency range. Some studies have revealed that the FDS curves have distinguished data that help detect bushing failures in their onset. However, there has not been a standard FDS interpretation method. Human experts’ opinions play a considerable role in the interpretation process. In this paper, a finite element method model of a 96 kV oil-impregnated paper bushing is built with different OIP moisture content. The FDS test is simulated under these moisture levels. Seven two-array and six one-array statistical indices are introduced to interpret the FDS results. The results have shown that all six one-array statistical indices, apart from average deviation (AVEDEV) and standard deviation (SD), can be perfect indicators of moisture levels of the OIP. Moreover, they can be used to assess the moisture content of the OIP bushings, and human errors are eliminated using this method.

The vibration transmissibility of paper honeycomb sandwich plate was tested and the vibration transmissibility curve was simplified and characterized. Based on the basic principle of vibration mechanics, the equation for calculating the energy dissipated by damping of paper honeycomb sandwich plate-block system during vibration was deduced. Furthermore, the effects of honeycomb structural parameters (cell length, sandwich plate thickness) and block mass on the damping energy dissipation were analyzed. The results showed that the curves of vibration transmissibility for paper honeycomb sandwich plate can be divided into three regions: plateau region, amplification region, and attenuation region. The vibration transmissibility ratio in different regions can be expressed as functions of frequency. The energy dissipated by damping of paper honeycomb sandwich plate-block system depends on its vibration transmissibility. If the vibration transmissibility ratio–frequency curve is obtained, the damping energy dissipation of the system can be calculated. The total energy dissipation of paper honeycomb sandwich plate-block system during vibration is about equal to that of plateau region, and the energy dissipated in amplification and attenuation region can be neglected. Different honeycomb structural parameters have the same effect on the damping energy dissipation of the system. Block mass has little effect on the damping energy dissipation in plateau region and the total energy dissipation during vibration but has a greater impact on the energy dissipation in the amplification and attenuation regions. The purpose of this paper is to provide a basic method for calculation of energy dissipated by damping and evaluation of anti-vibration property for packaging material.

The frequency domain spectroscopy (FDS) of the transformer oil-paper insulation can be simulated by using the finite element method (FEM). However, the effect of nonuniform aging on calculation results has not been included in previous simulation models. Given this issue, a novel simulation model including non-uniform aging is reported. In the present work, the oil-paper samples with various aging degrees are prepared to develop the composite structure of the oil-paper system. Then, the simulation models are constructed based on FEM. The comparison of measured FDS and simulated FDS is used to verify the feasibility of the proposed model. Present findings prove that the proposed model could predict the FDS of the transformer oil-paper insulation under non-uniform aging, which might be utilized to analyze its dielectric response property under non-uniform aging conditions.

Understanding the effects of water absorption on the geometry of a paper sheet is important for inkjet printing applications, since internal moisture content differences may cause unacceptable out-of-plane deformations. The present work focuses on moisture-induced deformations due to a moisture content that is uniform over the thickness of the sheet. Large enough in-plane differences will cause the sheet to buckle, leading to a wavy pattern at the edges of the sheet. Two approaches are utilized to study this for levels of moisture content up to and including the threshold for buckling. An analytical approach, based on geometrically nonlinear plate theory (von Karman theory), and a numerical one, using commercially available finite element software, are presented. As a first reference problem an isotropic circular plate, wetted uniformly at its center, is solved both analytically and numerically for the in-plane stress distribution, the buckling threshold, and the resulting buckling mode. Secondly, the same is done for an orthotropic rectangular plate, wetted at its edges. Here, in the analytical approach a Rayleigh–Ritz analysis is employed to approximate the buckling threshold. The latter is also calculated by numerical means. The results show that the methods provide results consistent with each other.

In order to improve structural efficiency, environmental performance, and constructability, a new type of one-way composite voided slab system (TUBEDECK) has been recently proposed which combines profiled steel decks with cast-in-situ RC slabs. Because eliminating concrete volume to optimize flexural strength can significantly reduce the shear strength of nonprestressed concrete or composite slabs without shear reinforcement, a clarification of the shear resistance capacity is required. In this study, shear tests on a total of 12 specimens were conducted with slab thickness, the presence or absence of voids and/or steel decks, and tension reinforcement ratio as variables. The results show that combined flexure and shear dominated the behavior of both voided (V) slabs and TUBEDECK (TD) slabs, and web-shear cracking did not affect strength. Predicted shear strength based on the minimum web width was too conservative. Conversely, the shear strength prediction equations, which were proposed on the basis of the real cross-sectional area of concrete, predicted the capacity of both V slabs and TD slabs from a reasonably conservative perspective. A discussion on the influence of moment–shear interaction is also included, and an interaction design model is proposed in a further investigation.

Circular action treatment (CAT) was developed for improving the strength of paper made from old corrugated containers (OCCs). The effects of the revolution speed of the circular blade, number of passes, and consistency of the stock were studied for application to paper recycling. The slowness, water retention value (WRV), and strength of the paper increased with increasing revolution speed of the circular blades and the passing time without changing the fiber characteristics (length, width, and kink angle) due to the improvement in flexibility and hydration degree of hornified fibers. However, the effect of CAT declined when the stock was passed more than 20 times. The thickening of the stock up to 25 % consistency enhanced WRV and strength of the resulting paper. Below 20 % consistency, the stock adhered to the wall of the CAT apparatus, whereas at higher consistency, the stock could not be treated effectively due to uneven impact. Consequently, when the OCC stock was thickened to 25 % and allowed to free fall from 20 times at the maximum revolution speed (875 rpm) of the circular blades, the strength of OCC paper could be effectively enhanced by CAT.

Oil-paper insulation high-voltage bushings are one of the most important power equipment in substations, and their insulation status is critical to the safety and the stabilization of the power system operation. During the production and operation, the bushing may be dampened because of the insufficient drying and impregnation or the intrusion of external moisture, which leads to the deterioration of oil paper insulation and threatens the reliability of bushing. Due to the special insulation structure of the bushing capacitor core, the distribution of moisture inside the bushing is usually non-uniform, especially when the moisture is intruded from the external environment. In this paper, a numerical simulation model of dual-unit laminated oil-paper and 110kV capacitor bushing is established. Then the frequency domain dielectric spectrum (FDS) characteristics of oil-paper insulation with different non-uniform moisture distribution are obtained by simulation. Different types of non-uniform moisture distribution include: non-uniform moisture distribution in different directions of the bushing, and different degrees of non-uniform moisture distribution. When the non-uniform moisture distribution of bushing is along the axial direction, different degrees of non-uniformity of moisture distribution have little effect on the FDS results; when the non-uniform moisture distribution of bushing is along the radial direction, the $\text{tan}\delta-f$ curve shows a clear dielectric loss peak, the characteristics of which are closely related to the degree of non-uniformity of the moisture distribution. Partial damping at the outermost side of the bushing or the end screen are more common in practice, and the FDS results of these two different types of damped bushing show different characteristic. This paper carried out a comprehensive FDS simulation study of different types of non-uniform dampened oil-paper insulation, which is of great significance for the evaluation of the insulation status of the oil-paper bushing.

I would like to introduce three wonderful papers to all our readers. Q. Xu and Y. Zhao from the Nanjing University of Aeronautics and Astronautics, China; X. Shen and K. Chen from the Nanjing Rongce Testing Technology Ltd, China; and Y. Huang from the University of Liverpool, U. K., authored the first paper "Absorption Cross Section Measurement of a Vehicle in Reverberation Chamber for Quick Estimation of Field Strength". For electromagnetic immunity testing of a vehicle, a reverberation chamber (RC) loaded with the vehicle-under-test has to be calibrated so that the necessary input power to generate the required field strength can be determined. In this paper, the average absorption cross section (ACS) of a vehicle in the frequency range of 80 MHz — 24 GHz is measured so that the required electric field strength in the RC loaded with a car can be estimated before the RC is constructed. Once the typical ACS of a car is known, one only needs to measure the Q factor of an unloaded RC and the Q factor of the RC loaded with a car can be predicted. This is very useful before the RC is constructed, as once the RC is built the unloaded Q factor cannot be increased.

The finite element model for paper honeycomb was constructed, and the finite element method of out-of-plane compression for the paper honeycomb was studied. Then four kinds of paper honeycomb with different structural parameters were simulated and analyzed using finite element software ABAQUS. Moreover, the results obtained from finite element method were verified based on the existing theoretical research results and experimental results, respectively. The results show that stress–strain curves obtained from finite element method clearly show the four deformation stages of the paper honeycomb under out-of-plane compression, which is basically consistent with the trend of the typical curve. The values of initial peak stress, plateau stress and densification strain are close to the theoretical results. The stress–strain curves and deformation contours coincide with experiments well. The differences of initial peak stress σpk, plateau stress σpl and densification strain εD between theoretical, finite element method and experimental results are less than 15%. Therefore, the finite element method can be used to analyze the stress–strain curves and deformation characteristics of paper honeycomb. In addition, the results also show that the thickness of specimen has little effect on the stress and strain. However, people often prefer to use the thicker paper honeycomb to get better cushioning effect in practical applications, which was explained.

The well-known McKee formula was derived in 1963 for symmetric fluting constructions. This paper presents investigations showing the influence of asymmetric properties, either geometric or concerning the elastic moduli. Paper properties of the base papers used are taken to calculate the panel properties of corrugated boards. From these results, the box failure is predicted. To do this, a model approximating the corrugated medium by triangles is presented. With this assumption, the bending stiffness of corrugated board, no matter how many flutes, can be predicted from paper data. Machine direction and cross direction are treated separately. The theoretical considerations are verified by measuring paper parameters such as short compression test (SCT), thickness, and bending stiffness, as well as edge compression test (ECT) and bending stiffness of corrugated board and box compression test (BCT) of the boxes. It can be stated that the prediction of using paper data instead of corrugated board data may lead to even better prediction results, as the measuring of bending stiffness at the board may sometimes be influenced by sampling inconveniences. Finally, thickness of the used base papers, as well as thickness of the manufactured board, appear to be the main influencing parameters. The McKee formula is robust enough to be applied for asymmetric corrugated board as well.

Pencils made out of waste or recycled paper is a new concept and is trending throughout the world. The aim of this product is to recycle paper and reduce cutting of trees by substituting wooden pencils. The technology of manufacturing pencils out of waste paper is new. It involves wrapping the paper around the graphite core using a suitable adhesive so that proper strength and desired properties equivalent to a wooden pencil can be achieved. This is done on a rolling machine comprising of a motor driven belt and 2 pressure plates which make the paper roll around the core due to friction between the belt and plates. Various types of paper can be used to make this product. Although the idea is unique, many problems are faced while trying to make a commercial grade product comparable to the wooden pencils. The first aim of this paper is explaining the process of manufacturing, pointing out the problems faced during manufacturing of commercial grade paper pencils and offer solutions to achieve a quality comparable to wooden pencils by providing empirical evidence. The second aim is to provide standardized data of manufacturing paper pencils after solving the problems faced in the process. First, the problems faced with the quality of paper pencils were identified and experiments were conducted by varying parameters to obtain a solution. Second, manufacturing data from 10 weeks was collected after fixing the problems with quality to obtain standardized manufacturing data for future production.

In this study, 12 commercially available paper towels were collected from the local market. Their tensile properties were investigated by Kawabata Evaluation System for Fabric (KES-F). Four tensile properties namely: (i) extensibility (EMT), (ii) tensile energy (WT), (iii) tensile resilience (RT) and (iv) linearity of WT (LT) were evaluated. Experimental results revealed that the tensile properties varied within the products. EMT was used as the key property for discussing the tensile properties of paper towels. However, when the different tensile properties were correlated, it was found that WT/RT, WT/EMT and RT/EMT had strong Pearson correlation. In addition, there was no significant statistically relationship between weight and thickness to EMT. Based on this study, it can provide some information about the tensile properties of paper towels in local market which may help the industry for further improving the product quality.

In this study, we chose 12 commonly available paper towels from the local market. The compression properties of the paper towels were examined by Kawabata Evaluation System for Fabric (KES-F). Three compression properties namely: (i) compressional linearity (LC), (ii) compression energy (WC) and (iii) compressional resilience (RC) were examined. The experimental results revealed that the compression properties varied within the different paper towels. RC vlaue was used as the key property for discussing the compression properties of paper towels. When different compression properties were correlated and analysed, it was found that no relationship was noted within different compression properties. On the other hand, there was not significant statistically relationship between weight and thickness to RC. It is hope that the results from this study can help the indurstry to improve the compression properties of paper towels for local market.

In this paper, we collected 12 commercially available paper towels from the local market and their shearing properties were evaluated by Kawabata Evaluation System for Fabric (KES-F). Three properties namely: (i) shear rigidity (G), (ii) shear stress at 0.5º (2HG) and (iii) shear stress at 5º (2HG5) were studied. Experimental results revealed that the shearing properties varied within the products. G was used as the key property for discussing the shearing properties of paper towels. However, in correlating different shearing properties, it was found that 2HG and 2HG5 had strong Pearson correlation. However, no significant statistically relationship between weight and thickness to G was found. This study may provide data for the industry for the improvement of shearing properties of paper towels for local market.

12 commercially available paper towels were collected from the local market and studied in this paper. Kawabata Evaluation System for Fabric (KES-F) was used for evaluating their bending properties. Two bending properties namely: (i) bending rigidity (B) and (ii) bending moment (2HB) were evaluated. Experimental results indciated that the bending properties varied within the products. B was used as the key property for discussing the bending properties of paper towels. When the correlations of different bending properties were investigated, it was found that no significant was found between B and 2HB. However, there was significant statistically relationship between weight and B but no relationship between thickness and B. With the use of the results, the product developer could improve the bending properties of the paper towels.

In this study, 12 commercially available paper towels were collected from the market. Their shearing properties were evaluated by Kawabata Evaluation System for Fabric (KES-F). Three properties namely: (i) coefficient of friction (MIU), (ii) deviation of MIU (MMD) and (iii) geometric roughness (SMD). Experimental results revealed that the surface properties varied within the products. When different properties were correlated, it was found that there was not significantly relationship between MIU, MMD and SMD. However, weight and thickness had well statistically relationship to SMD.

The soil-water retention curve defines a relationship between the water content of a soil and the corresponding pressure at which the soil-water-air is in equilibrium. In cases in which undisturbed sampling are not feasible, especially for nonplastic and low-plastic soil fabrics, reconstituted soil samples are required. A newly designed mold was devised for use with reconstituted soil samples and the filter paper test. The newly designed mold consisted of a #200 wire mesh that allows for three-dimensional vapor flow. Implementing this new apparatus in conjunction with an energy-based reconstitution protocol minimizes inconsistencies across the test specimen such that variabilities associated with the filter paper testing method can be isolated and calibration curves verified. Calibration procedures are assessed and results are presented based on axis translation and verified by tensiometer measurements. This redesigned filter paper test was then conducted over a range of nonplastic to low-plastic soils yielding comparable results with published field studies and data bases. It can be concluded from this investigation that the filter paper method, using an energy-based reconstitution method and a mesh mold, is comparable to non-filter paper testing methods and is preferable for some applications because of its simplicity and relative short testing times.

To explore the application of environmental protection material-paper straw board in cold-formed thin-walled steel (CFS) structures and further develop the sheathing system, an innovative CFS framing wall sheathed by paper straw board (CFSSB) is proposed. Eight CFSSB composite wall specimens and one CFS frame without sheathing were tested under monotonic and reversed cyclic horizontal loads to study the shear performance of the CFSSB composite wall. Also, the shear performance of the wall specimens can be obtained. The key parameters include the value of the vertical load and the form of the CFS frame in this experimental program. By analyzing the specimen’s failure forms and failure process, the characteristic values of the bearing capacity, lateral stiffness, ductility coefficient and energy dissipation coefficient are obtained. The results show that the existence of paper straw board and adding diagonal braces to the CFS frame can significantly improve the shear capacity of CFSSB composite walls. The favorable seismic performance of the CFSSB composite wall was demonstrated in the experiment. In addition, a finite element model for CFSSB composite wall is developed using the software package ANSYS. The finite element analysis (FEA) results show a good agreement with the experiment results in terms of failure modes and skeleton curves, which verify the feasibility of the FEA model. Furthermore, extensive parametric analysis was carried out to analyze the factors affecting the shear capacity of the CFSSB composite wall. The FEA results show that the spacing of studs and self-tapping screws greatly influences the shear capacity of walls. Moreover, based on the failure of the screw connections, a formula for calculating the shear capacity of the CFSSB composite wall is proposed. The results of the formula calculation show good agreement with the experiment and FEA results, and it can provide a reference for engineering design.

This study investigates roll paper fire using laboratory-scale experiments, with emphasis on water transport on burning surfaces for sprinkler suppression. Freeburn, water transport and suppression experiments were conducted using different types of paper with various basis weight and water absorptivity. For fire suppression, the experimental results showed different water transport patterns that are sensitive to the burning surface conditions. This is in contrast to the water transport under no fire conditions in straight vertical rivulets exhibiting highly non-uniform distribution along the roll perimeter. For roll paper fire growth, both surface delamination and exfoliation play a crucial role, with the delamination length increasing either linearly or exponentially with time and the exfoliation rates strongly dependent on paper basis weight. Although the effects observed at the small scale in this work may have differences from those at large scales, the experimental results yield insights for better understanding of fire growth and suppression mechanisms and provide extensive data for numerical model development and validation.

The present paper explores the short span compression tester (SCT) as a means to experimentally determine the transverse shear moduli of paper. These moduli, which are known to be difficult to determine by any other means, are of importance for the behavior of paper during tissue manufacturing and in the converting and embossing of paperboard. Testing was conducted on paper of two different grammages both in MD and in CD. By applying the Timoshenko–Engesser theory for buckling of shear compliant materials, estimates of the transverse shear moduli were obtained through the measured SCT values and standard measurements of the Young’s modulus and the thickness. These estimates were evaluated by detailed FE-analyses of the SCT setup incorporating initial geometrical imperfections representative for real test conditions. It was found that the Timoshenko–Engesser theory gives estimates of the transverse shear moduli that are within an accuracy well applicable for most engineering purposes. The results suggest that the method is at least as accurate as any other, more involved, method that could be used for the purpose.

The mechanical response of three different structural core sandwich panels in out-of-plane compression and shear has been analyzed. Specific core shapes examined are arc-tangent, wavy trapezoidal and hemispherical. Unit cells consisting of representative elements of the core attached to face sheets were selected for analysis. Both face sheets and core were assumed made from paper. Finite element analysis employing large deformation and rotations and orthotropic elastic–plastic behavior was used. The results show that the arc-tangent and trapezoidal cores are prone to collapse by extensive bending and buckling, whereas the hemispherical core behaved more stably in compression and shear. Core sheets with a hemispherical shape were prepared from copy paper sheets in a specially designed forming machine. Sandwich test specimens were prepared from this core and tested in out-of-plane compression, and the load-displacement response was compared to predictions from finite element simulations. The experimental and finite element results were consistent.

Due to the different overvoltage waveforms and the different distribution of the waveform parameters, the failure characteristics of insulating medium under these overvoltage waveforms are significantly different. However, the failure probability characteristics are closely related to the risk assessment of insulation failure of power system. Meanwhile, the failure probability characteristics of insulating medium under different overvoltage waveforms are not fully understood. Therefore, it is necessary to carry out research on the difference of failure probability characteristics of insulating material under different impulse voltages. In this paper, a double exponential impulse wave (DEIW) and bipolar oscillatory attenuated impulse wave (BOAIW) test platform was set up. Then, we obtained the failure probability of oil-immersed insulation paper (OIP) for transformer under the DEIW and the BOAIW. The differences and commonalities of the failure probability characteristics of OIP under different waveforms were further analyzed. Finally, we realized the prediction of the failure probability characteristics of oil-paper insulation under different impulse voltages.

Previous studies have confirmed that the insulation status of oil-paper transformer can be qualitatively analyzed by its time domain dielectric spectral characteristics. However, it is more important to evaluate the insulation condition of transformers quantitatively in engineering practice. An evaluation system based on characteristics obtained by the return voltage measurements is constructed in this paper for the quantitative evaluation of the insulation state of oil-paper transformers. First, data of characteristics of transformer are normalized and neighborhood radius of each characteristic are calculated. Then, the decision table of oil-paper insulation diagnosis system is generated based on neighborhood rough set theory. Moreover, attribute reduction is carried out to the decision table and the best rules are extracted. Finally, the oil-paper insulation state evaluation system is constructed based on the historical database. Five transformers of known insulation status have verified the accuracy of the evaluation system.

Centre-notched tension and double-edge-notched tension tests were conducted using specimens of copy paper in order to determine the Mode I critical J-integral. The crack length was varied during the test, and the effects of the test method and crack length were examined. The critical J-integral obtained from the centre-notched tension test was significantly smaller than that obtained from the double-edge-notched tension test. In both tests, the critical stress intensity factor decreased as the initial crack length increased. When the crack length correction was performed, however, the Mode I critical J-integral could be accurately obtained while reducing the aforementioned dependencies.