Regulating the Deformation Properties of Paper by Varying the Degree of Its Anisotropy

Mechanical properties are crucial in assessing the paper quality. Deformation and strength properties of paper are determined by the strength and stiffness of the interfiber and intermolecular hydrogen bonds. The contribution ratio of interfiber and intermolecular hydrogen bonds to the strength of paper can be changed by adjusting the degree of its anisotropy. The article presents the results on a study of the deformation properties of laboratory anisotropic paper samples from kraft bleached softwood pulp with a beating degree of 30 °SR. The samples had basic weight of 90 g/m2 and the degree of stiffness anisotropy TSIMD/CD of 1.75–4.08. They were made by using Techpap SAS automatic dynamic handsheet former (Grenoble, France), with varying forming parameters – diameter of the nozzle, motion speed of the forming wire, and injecting speed of pulp. Deformation properties were determined by tensile test and processing of the stress-strain dependence (σ−ε). The outcomes have shown that, an increase of the fiber orientation degree in paper structure by changing the forming parameters caused a change in the nature of the paper deformation under tension. Increasing the fiber orientation degree in the structure of paper made it possible to increase the strength by 55 %, tensile stiffness by 63 % in the machine direction, while reducing the extensibility by 10 %. In the cross direction, it was possible to decrease tensile stiffness by 33 %, strength by 55 %, and increase the extensibility by 5 %. Anisotropy of tensile strength was 1.73–6.00. The greatest effect was obtained for the elasticity modulus in the pre-failure zone E2 (2.8–38.6). It means that, fiber orientation had a key importance when large deformations in the samples took place. The established quantitative regularities allowed optimizing the values of the deformation and strength properties of paper, and their ratio in the machine direction and cross direction due to the variation of the forming parameters. For citation: Rech D., Potasheva A.N., Kazakov Ya.V. Regulating the Deformation Properties of Paper by Varying the Degree of Its Anisotropy. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 174–184. DOI: 10.37482/0536-1036-2021-5-174-184

A Cross-Direction and Progressive Network for Pan-Sharpening

In this paper, we propose a cross-direction and progressive network, termed CPNet, to solve the pan-sharpening problem. The full processing of information is the main characteristic of our model, which is reflected as follows: on the one hand, we process the source images in a cross-direction manner to obtain the source images of different scales as the input of the fusion modules at different stages, which maximizes the usage of multi-scale information in the source images; on the other hand, the progressive reconstruction loss is designed to boost the training of our network and avoid partial inactivation, while maintaining the consistency of the fused result with the ground truth. Since the extraction of the information from the source images and the reconstruction of the fused image is based on the entire image rather than a single type of information, there is little loss of partial spatial or spectral information due to insufficient information processing. Extensive experiments, including qualitative and quantitative comparisons demonstrate that our model can maintain more spatial and spectral information compared to the state-of-the-art pan-sharpening methods.

Study on technology of greaseproof paper for dry food packaging

This paper presents the research results that established the main technological conditions in the production of greaseproof paper, used as the packaging of dry food as the proportion of pulp types, the degree of the beating of pulp, the use of chemicals and oil and greaseproof resistant agent to the properties of the paper on a laboratory scale. At the same time, experimental production and technology conditions were regulated on a 3 ton/day capacity line. The paper quality produced is equivalent to the imported paper products of the same type which is consumed in the market: basis weight: 42.5 g/m2; tensile breaking length: MD (Machine Direction): 7,520 m, CD (Cross Direction): 3,740 m; tear index: MD: 6.8 mN.m2/g, CD: 5.4 mN.m2/g; burst index: 5.6 kPa.m2/g; Cobb60: 17.2 g/m2; KIT rating: 8; ensuring food safety and hygiene.

Asymmetric reinforcement in Lucania killifish: assessing reproductive isolation when both sexes choose

Reinforcement can occur when maladaptive hybridization in sympatry favors the evolution of conspecific preferences and target traits that promote behavioral isolation (BI). In many systems, enhanced BI is due to increased female preference for conspecifics. In others, BI is driven by male preference, and in other systems both sexes exert preferences. Some of these patterns can be attributed to classic sex-specific costs and benefits of preference. Alternatively, sex differences in conspecific preference can emerge due to asymmetric postzygotic isolation (e.g., hybrid offspring from female A × male B have lower fitness than hybrid offspring from female B × male A), which can lead to asymmetric BI (e.g., female A and male B are less likely to mate than female B and male A). Understanding reinforcement requires understanding how conspecific preferences evolve in sympatry. Yet, estimating conspecific preferences can be difficult when both sexes are choosy. In this study, we use Lucania killifish to test the hypothesis that patterns of reinforcement are driven by asymmetric postzygotic isolation between species. If true, we predicted that sympatric female Lucania goodei and sympatric male L. parva should have lower levels of BI compared with their sympatric counterparts, as they produce hybrid offspring with the highest fitness. To address the problem of measuring BI when both sexes are choosy, we inferred the contribution to BI of each partner using assays where one sex in the mating pair comes from an allopatric population with potentially low preference, whereas the other comes from a sympatric population with high preference. For one hybrid cross direction, we found that both female L. parva and male L. goodei have high contributions to BI in sympatry. In the other hybrid cross direction, we found that only female L. goodei contribute to BI. Sympatric male L. parva readily engaged in hybrid spawnings with allopatric L. goodei females. These results indicate that both asymmetric postzygotic isolation and the traditional sex-specific costs to preference likely affect the nature of selection on conspecific preferences and target traits.

Distribution of Bending Stiffness of Orthotropic Fibrous Material Based on an Example of Corrugated Board

Commonly known methods for calculating the bending stiffness of corrugated board allow to calculate values related to the machine and cross direction of corrugated board but do not allow to calculate bending stiffness in any intermediate direction. The article presents a method for calculating bending stiffness in any direction in the plane of corrugated board, on the basis of the bending stiffness values in the machine and cross direction. Comparing the results of measurements of bending stiffness in selected directions with those of their calculations, the method proposed was verified and its practical usefulness confirmed.

The Effect of Radiation Sterilization on the Stress-Strain Properties of Non-Woven Materials -Based on Polypropylene

Non-woven materials are widely used for the manufacture of disposable medical clothing and underwear. Radiation is widely used to sterilize single-use medical devices. The paper analyzes the effect of ionizing radiation at absorbed doses of 0-60 kGy on the stress-strain properties of medical non-woven spanmelt material based on polypropylene obtained by blow-molding technology. It has been established that ionizing radiation significantly reduces the breaking load and elongation in the machine and cross directions of the web. For this type of material, the most critical is the decrease in strength in the cross direction of the web, primarily because the level of strength in the cross direction of spanmelt materials is generally low. Sterilization by ionizing radiation further reduces strength and leads to the fact that non-woven materials irradiated with an absorbed dose of 50-60 kGy are close to unacceptable values in accordance with the requirements of EN 13975-2011.

Calculation of Honeycomb Paperboard Resistance to Edge Crush Test

The article presents the method of calculating the edge crush test (ECT) of honeycomb paperboard. Calculations were made on the basis of mechanical properties of paper raw materials used for the production of cellular paperboard and geometrical parameters describing cellular paperboard. The presented method allows ECT calculation of honeycomb paperboard in the main directions in the paperboard plane; i.e., machine direction (MD) and cross direction (CD). The proposed method was verified by comparing the results of calculations with the results of ECT measurements of paperboard with different geometrical parameters made of different fibrous materials.

Evaluation of in-plane compressive densification strain of honeycomb paperboard

The compressive densification strain of honeycomb paperboard is one of the important parameters which affect the energy absorption property of honeycomb paperboard. The in-plane bearing mechanism of honeycomb paperboard in plastic zone was analyzed based on compression tests of the single row and multi-rows of honeycomb paperboard. The result indicates that the core layer plays a supporting role in resisting the buckling of the face layer. The double inner folds are formed in machine direction and the symmetrical inner folds are formed in cross direction in a honeycomb core. The core single wall and the face layer play a critical role in the load bearing in machine direction, and the core double walls, core single wall, and face layer all play critical roles in the load bearing in cross direction. On this basis, the evaluation equation of the compressive densification strain was obtained based on the energy absorption efficiency method and geometric scale effect, which are verified so that the experiment and test results are in good agreement.