PAPERmaking! Vol9 Nr2 2023

PAPER making! The e-magazine for the Fibrous Forest Products Sector

Produced by: The Paper Industry Technical Association

Publishers of: Paper Technology International ®

Volume 9 / Number 2 / 2023

PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® FROM THE PUBLISHERS OF PAPER TE Volume 9, Number 2, 2023 CONTENTS:

FEATURE ARTICLES: 1. Testing : Determining the shape of a paper sample in in-plane compression test. 2. Tissue : The value of data for environmental sustainability assessment. 3. Decarbonisation : High-temperature heat pumps for selected industry sectors. 4. Environment : Conversion of paper waste & rejects into materials & energy. 5. Bio-Energy : Emission factors of industrial boilers burning biomass-derived fuels. 6. Pulping : Achieving optimal paper properties: a new approach for kraft pulping. 7. Wood Panel : Engineered transparent wood composites: a review. 8. Driving : Driving tips for the summer. 9. Proofreading : Tips for effective proofreading. 10. Speed Reading : How to absorb information quickly and effectively.

11. Delegation : How to delegate tasks to your team. 12. Safety Hazards : Prevention of slips, trips and falls.

SUPPLIERS NEWS SECTION: News / Products / Services :

Section 1 – PITA Corporate Members: ABB / VALMET Section 2 – PITA Non-Corporate Members VOITH Section 3 – NON-PITA SUPPLIER MEMBERS mycon GmbH Advertisers: ABB & VALMET

DATA COMPILATION: Events : PITA Courses & International Conferences / Exhibitions

Installations : Overview of equipment orders and installations between April and June Research Articles : Recent peer-reviewed articles from the technical paper press Technical Abstracts : Recent peer-reviewed articles from the general scientific press The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International ® and the PITA Annual Review , both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating .

Contents

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PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® FROM THE PUBLISHERS OF PAPER TE Volume 9, Number 2, 2023

A New Technique for Determining the Shape of a Paper Sample in In-Plane Compression Test Using Image Sequence Analysis PAWEŁ PEŁCZYNSKI , 1 WŁODZIMIERZ SZEWCZYK , 1 MARIA BIENKOWSKA 1 & ZBIGNIEW KOŁAKOWSKI 2 The article presents a new technique for analyzing phenomena occurring during the measurement of the strength properties of paper in the conditions of compression of the tested samples with forces acting in the paper plane. The technique is based on collecting data on the current distance of the clamps holding the tested sample and the force exerted on the sample using a universal testing machine and on the simultaneous recording of image sequence of the sample during the measurement. Next, the resulting images are subjected to processing and analysis, the purpose of which is to extract information about the shape of the sample edge in all phases of the measurement. Its advantage is the ability to determine the deflection arrow of the sample and describe its shape using the selected function given by the analytical parametric formula. It will be helpful in further research on the development of an analytical model describing the phenomena occurring during paper compression, and a method to determine the mechanism of paper destruction and the corresponding maximum force that destroys a paper sample. Contact information: 1. Centre of Papermaking and Printing, Lodz University of Technology, Wólczanska 221, 95- 003 Łódz, Poland. 2. Department of Strength of Materials, Lodz University of Technology, Stefanowskiego 1/15, 90- 537 Łódz, Poland. Appl. Sci. 2023, 13, 1389.

https://doi.org/10.3390/app13031389 Creative Commons Attribution 4.0 License

The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International ® and the PITA Annual Review , both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating .

Article 1 – Testing using In-Place Compression

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applied sciences

Article A New Technique for Determining the Shape of a Paper Sample in In-Plane Compression Test Using Image Sequence Analysis Paweł Pełczyn´ ski 1, * , Włodzimierz Szewczyk 1 , Maria Bien´ kowska 1 and Zbigniew Kołakowski 2

1 Centre of Papermaking and Printing, Lodz University of Technology, W ó lczan´ ska 221, 95-003 Ł ó dz´, Poland 2 Department of Strength of Materials, Lodz University of Technology, Stefanowskiego 1/15, 90-537Ł ó dz´, Poland * Correspondence: pawel.pelczynski@p.lodz.pl; Tel.: +48-426313816 Abstract: The article presents a new technique for analyzing phenomena occurring during the measurement of the strength properties of paper in the conditions of compression of the tested samples with forces acting in the paper plane. The technique is based on collecting data on the current distance of the clamps holding the tested sample and the force exerted on the sample using a universal testing machine and on the simultaneous recording of image sequence of the sample during the measurement. Next, the resulting images are subjected to processing and analysis, the purpose of which is to extract information about the shape of the sample edge in all phases of the measurement. Its advantage is the ability to determine the deflection arrow of the sample and describe its shape using the selected function given by the analytical parametric formula. It will be helpful in further research on the development of an analytical model describing the phenomena occurring during paper compression, and a method to determine the mechanism of paper destruction and the corresponding maximum force that destroys a paper sample.

Keywords: strength properties of paper; analysis of digital images; modelling of the shape of a paper sample; deflection arrow

Citation: Pełczyn´ ski, P.; Szewczyk, W.; Bien´ kowska, M.; Kołakowski, Z. A New Technique for Determining the Shape of a Paper Sample in In-Plane Compression Test Using Image Sequence Analysis. Appl. Sci. 2023 , 13 , 1389. https://doi.org/ 10.3390/app13031389

1. Introduction Paper is an orthotropic material commonly used for the production of corrugated and cellular cardboard, from which a variety of packaging is then produced [1,2]. Their usefulness is determined by the strength properties, which depend to a large extent on the properties of the paper itself [3–9]. At the same time, it is desirable to minimize the weight of the package while maintaining the required strength. In order to avoid time- consuming, experimental selection of the material composition of the cardboard from which the packaging is made, it is increasingly used to predict their strength properties by means of calculations that take into account the properties of the papers used in their production [10–14]. One of the important properties is the resistance to edge crushing measured in the compression test at short fastening—SCT [15]. Due to the orthotropy of the paper, resistance to crushing is determined in two main directions, namely MD (machine direction) and CD (cross direction). However, the test does not take into account the phenomenon of buckling of the tested sample, which occurs when using longer sample attachment lengths and is commonly ob- served in corrugated cardboard packaging. Analysis of the compressive strength of various materials in the buckling state has been of interest to researchers for many years because it is of great importance for estimating the load capacity of mechanical structures [16–19]. However, the study of paper properties in this area was usually limited to simple com- pression tests and was not combined with simultaneous observation of the shape of the compressed samples. Modern methods of processing and analyzing digital images make it possible to observe changes in the shape of bodies subjected to external forces on the basis of the

Academic Editor: Milena Pavl í kov á

Received: 21 December 2022 Revised: 11 January 2023 Accepted: 16 January 2023 Published: 20 January 2023

Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

Appl. Sci. 2023 , 13 , 1389. https://doi.org/10.3390/app13031389

https://www.mdpi.com/journal/applsci

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analysis of their series of images [20,21]. Thanks to advances in electronics, it is now possible to record sequences of images of processes occurring during strength tests of various materials in real-time. The series of images obtained in this way can be reviewed in any way, focusing on the significant phenomena occurring during the experiment, and can also be subjected to automatic analysis, the purpose of which is a quantitative description of a given process. An example of such a solution is the Lenso vision system for recording the surface of materials subjected to mechanical testing. Thanks to the use of Digital Image Correlation [22,23] in the square areas of successive images in the sequence, they allow for precise estimation of local deformations of the observed surfaces. Vision systems are also used in papermaking and printing to detect defects and assess the quality of produced paper or print [24]. This is possible thanks to the use of advanced algorithms for detecting defects visible in subsequent images of the recorded sequence, and often also algorithms for automatic recognition of the type of defect. Implementation of these operations in real time requires the use of computers with high computing power. This allows to control the production line based on the information received and improve the parameters of the production process or reject a defective product. Observing the shape of paper samples during the crushing resistance test allows for associating changes in the shape of the sample with the magnitude of the force acting on it during the test. To make this possible, it is necessary to record images of the sample being tested and synchronize the resulting series of images with data from the machine.

2. Materials and Methods 2.1. Measuring Setup

The use of digital image analysis methods in measuring the crushing resistance of pa- per required solving the problem of synchronization of measurement in a universal testing machine with the recording of images of the tested samples. In order to simultaneously record the displacement of the moving handle of the testing machine and the force acting on the compressed sample and the images of the sample to be tested, the measuring setup shown in Figure 1a was prepared.

( a ) ( b ) Figure 1. Viewof ( a ) the measuring station, ( b ) the handles of the testing machine with sticked checkerboard patterns and the paper sample to be tested. The stand consists of a testing machine (1) Zwick Roell Z 010, an SCT test holder (2), a camera placed on a tripod (3)—a Canon EOS 6D Mark II full-frame DSLR with a Canon MP-E 65 mm f/2.8 1–5 × Macro lens (4) and an illuminator providing constant illumination with the possibility of adjusting its direction (not visible in the photo). This

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allows to achieve good contrast between the edge of the paper sample under examination and the background. In order to adjust the sharpness of the image, the camera is attached to the tripod via a setting sledge (5). This makes it possible to adjust the position of the camera in two horizontal axes—parallel and perpendicular to the optical axis of the camera. The camera lens allows to manually change the scale of reproduction in the range of 1 to 5, which gives the size of the recorded fragment of the paper sample in the range of 7.2mm × 5.8 mm to 36 mm × 24 mm. In the prepared measuring setup, magnifications in the range of 4 to 5 were used. Patterns of checkerboard (8) with a length of a single square of 1 mm (Figure 1b) were sticked to the fixed (6) and movable (7) clamps of the testing machine. It allowed to track the movement of the handle (6) and to determine the spatial resolution of the recorded images. The measurement begins by placing the tested paper sample (9) in the SCT holders of the testing machine, setting the desired focal length of the lens and positioning the camera in such a way that the sample and the checkerboard fragments containing at least two intersections between its fields are in the field of vision. Next, the force value is reset, the recording of the sequence of photos is started and after recording 3–4 images, the measurement is initiated in the machine. The measurement ends when the set displacement of the movable handle is reached. During the entire measurement, a recording of the sequence of images of the sample is performed along with fragments of handles with sticked checkerboards. 2.2. A Sequence of Operations Included in the Developed Measurement Technique The developed measurement technique consists of a series of operations that must be performed in order to obtain correct measurement results and their analysis. The flow diagram of the entire measurement is shown in Figure 2. The tested material and processed data are presented in the figure by means of gray rectangles. Operations included in the measurement process are shown in light blue rectangles with rounded corners.

Synchro- nisation measure ment data

Sample compression test in UTM

UTM measure- ment data

Conditio- ning the paper and preparing samples for testing

Measure- ment result: flow of measured quantities and estimated process parameters

Analysis of syn- chronis ed UTM data and images

Tested paper

Recording image sequence of tested

Image prepro- cessing

Sequence of images

sample images

Figure2. Flow diagram of the entire measurement procedure. 2.3. Developed Image Processing and Analysis Technique The recorded sequence of images was subjected to pre-processing and analysis. Pre- processing consisted of the following stages: • conversion of a series of RAW images to TIFF format with optional reducing the size of a digital image to reduce data volume, • extracting information about the recording time of each photo in the sequence with an accuracy of 1/100 of a second, • conversion of color images to grayscale,

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• cropping obtained images to the following regions: the examined paper sample, the checkerboard on the movable handle, and the checkerboard on the fixed handle, • linear filtering of the sample image by means of a filter that enhances the vertical edges in the image; its mask is shown in Figure 3, • linear filtering of checkerboard images using a filter that emphasizes the corners of the checkerboard fields in the image; its mask is shown in Figure 4.

Figure3. Filter mask designed to emphasize edges in an image.

Figure4. Filter mask designed to emphasize checkerboard corners in an image.

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The results of filtering the sample image are shown in Figure 5a. Figure 5b shows the image of the sample itself with the detected edges of the sample: left (green) and right (red). Detecting the left edge is very difficult due to the low contrast in the image, hence in further analysis it was decided to rely on the detection of the right edge. This cannot be generalized to all cases. The contrast depends on the direction and lighting of the sample. In the future, choosing the right filter mask should be an option for the analysis algorithm.

( a ) ( b ) Figure5. ( a ) The result of filtering the image of the paper sample during the measurement, ( b ) the image of the sample with the detected left edge marked in green and the right edge in red. Figure 6 shows the result of filtering the checkerboard images placed on both handles of the testing machine and the places where the corners marked with red dots were detected. To detect the corners between the white and black fields, regardless of their order, filtering was repeated twice with the filter mask rotated 90 degrees. Next, in the obtained images, the places of the corners were detected independently by detecting the maxima in the images after the filtering and the resulting information from both images was combined.

( a )

( b )

( c )

( d )

( e ) ( f ) Figure 6. The result of filtering the checkerboard image on the moving ( a , b ) and still ( d , e ) handle and images of the handles themselves ( c , f ) with the corner detection points marked in red. Pictures ( b , e ) show the result of filtering with a filter with a mask rotated by 90 ◦ .

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The coordinate sets of the points of the detected edges and corners were input informa- tion to the algorithm for the analysis of image data. The image coordinates were converted to metric coordinates (mm) based on information about the spatial resolution of the images and the arbitrarily assumed place of the beginning of the coordinate system (associated with the place where the sample is handled in a still holder). The shape of the edge of the test sample in subsequent images of the recorded sequence is shown in Figure 7.

Figure7. An example of the shape of the edge of the sample being tested in subsequent images of the recorded sequence. The apparent movement of the lower end of the sample edge is the result of limiting the analysis field to the area of correct edge detection in the image. The assumed origin of the coordinate system, associated with the edge of the still handle, is below the bottom edge of the image. 2.4. Synchronization of Image Data and Measurement Results from the Testing Machine The average values of the coordinates of the corners of the movable and stationary checkerboard were used to determine the displacement of the handle at the moments of recording individual photos. Based on this information, the time of photo recording as a function of the time of measurement data acquisition in the testing machine was estimated, as shown in Figure 8. The result was the synchronization of data recording times from two different sources.

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Figure8. Displacement of the handle of the testing machine estimated from a series of images before and after synchronization with data from the machine. 2.5. Estimation of Deformation Parameters of the Tested Paper Sample The measurement data obtained as a result of the pre-processing and analysis of the images were further analyzed in order to determine the value of so-called the deflection arrow of the paper sample and the parameters of the sinusoidal function modelling the shape of the sample edges. This is preceded by a rotation of the coordinate system of the machine to position the edge of the sample at the beginning of the test in a vertical direction. This operation is performed on the basis of the coordinates of the sample mounting in the machine holders. After this correction, the deflection arrow is defined as the difference in the horizontal coordinate of the places of attachment of the sample in the handles and the place of the greatest deflection of the sample. The shape of the sample is then modelled using a sinusoidal function of image coordi- nates x = f( y ): x = C + A · sin 2 · π · y Pr + ϕ , (1) where: C -constant—the shift relative to the beginning of the coordinate system (it can change in subsequent photos as a result of, for example, camera vibrations, it is not important in measuring the deflection of the sample), A —amplitude of the sine wave function modelling the deflection, Pr —the period of the sine wave modelling the deflection (at the initial stage of measurement, before the buckling of the sample, it cannot be determined accurately), ϕ —the initial phase of the sine wave modelling the deflection (not relevant from the point of view of deflection analysis, but must be a variable in order to match the model well with the measurement data). The desired values of the parameters of the sample shape modelling function are searched in the optimization procedure that minimizes the SSE Sh error between the mea- surement data and the modelling result. The error is described by Equation (2):

2 · π · y i Pr

+ ϕ )

SSE Sh = ∑

x i − C − A · sin (

(2)

where: i —index of the point at the edge of the test sample,

x i —the horizontal coordinate of the i -th point at the edge of the sample, y i —the vertical coordinate of the i -th point on the edge of the sample.

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2.6. An Example of Analysis of Measurement Data—Crushing a Paper Sample Subjected to the Test with a Clamping Length of 4 mm The results of the measurements recorded during the MD crushing test of the packag- ing paper and the analysis of the images recorded at that time and the modelling of the sample shape using the function given by the Formula (1) are shown in Figures 8–10.

Figure 9. The results of compression analysis of a 4 mm long paper sample at the time of the appearance of the sample buckling.

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Figure10. The results of the compression analysis of the paper sample at a clamping length of 4 mm at the maximum compressive force. Meaning of the individual charts in each drawing: (a)—an image of the sample with the edge detected, (b)—the shape of the detected edge in the coordinate system determined on the basis of the indicated points of attachment of the sample, (c)—the shape of the force curve as a function of displacement of the handle with the marked place of recording of the shown image, (d)—the value of the deflection arrow as a function of displacement of the movable handle, (e)—the value of the deflection arrow as a function of force, (f)—work on deformation of the sample as a function of displacement of the handle,

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(g)—the amplitude value of the sine wave function modelling the shape of the sample as a function of displacement of the handle, (h)—the period of the sinusoidal function modelling the shape of the sample as a function of displacement of the handle, (i)—the value of the sample shape modelling error as a function of the handle displacement. A round, red marker on the background of curves representing individual functional dependencies shows the obtained values in the discussed phase of the compression process. Figure 9 shows the state of the sample at the time of transition from the pure com- pression phase to the buckling phase of the sample. In the moments preceding this state, modelling the shape of the sample with a sinusoidal function does not make sense. There- fore, graphs from (g) to (i) in Figure 9 begin with the place marked with a dot. Figure 10 shows the state of the sample when the maximum force is reached. Up to this point, the approximation of the shape of the sample using the function described by the Formula (1) is characterized by a small error value, which means that the buckling takes the shape of a sinusoid until the maximum force is reached. Figure 11 shows the condition of the sample after its destruction. In this state, the approximation of the sample shape using the function described by the Formula (1) is not very accurate, as indicated by the increasing value of the modelling error. The sample takes a shape similar to two sections connecting the connection points.

Figure11. Cont.

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Figure11. The results of compression analysis of a 4 mm long paper sample after breaking the sample. 3. Results The results of measurements made with sample clamping lengths from 0.7 mm to 5 mm are presented. A measurement experiment was performed to study the behavior of samples of packaging paper crushed in the direction of MD. The sample was 15 mm wide, as in a typical SCT test. The standard clamping length in the SCT test is 0.7 mm. However, different values of the sample connection length were used: 0.7 mm, 1.3 mm, 2 mm, 3 mm, 4 mm and 5 mm. The thickness of the paper was 0.14 mm. Figure 12 shows the shape of a curve representing the dependence of the compressive force of a paper sample on the displacement of the movable handle with fastening lengths from 0.7 mm to 5 mm.

Figure12. Shape of the dependence of the compressive force of the paper sample on the displacement of the movable handle at the fastening lengths: ( a ) 0.7mm, ( b ) 1.3mm, ( c ) 2mm, ( d ) 3mm, ( e ) 4mm, ( f ) 5mm.

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As the length of the fastening increases, a tendency to decrease the maximum force occurring during the test is observed. Curves for a length of 0.7–5 mm increase rapidly until the maximum value is reached, and then fall sharply, but with a smaller gradient. Table 1 shows the maximum values of the compressive force as a function of the clamping length.

Table1. Dependence of the maximum value of the compressive force on the connection length.

Connection Length, mm 0.7

1.3

2.0

3.0

4.0

5.0

Maximum value of compressive force, N

35.42

32.57

30.56

27.04

20.17

16.20

At the same time, it can be seen in Figure 13a–c that with fastening lengths of less than 3 mm at the moment of reaching the maximum force no buckling is observed. With longer lengths of fastening, the buckling has the shape of a sinusoid fragment.

( a )

( b )

( c )

( d ) ( f ) Figure 13. Shape of the edge of the compressed paper sample when the maximum force is reached at the clamping lengths: ( a ) 0.7mm, ( b ) 1.3mm, ( c ) 2mm, ( d ) 3mm, ( e ) 4mm, ( f ) 5mm. ( e ) Figure 14 shows the shape of the samples compressed at the time of destruction for the plug-in lengths to be analyzed.

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( a )

( b )

( c )

( d ) ( f ) Figure14. Shape of the edges of the compressed samples at the time of destruction for the connection length: ( a ) 0.7mm, ( b ) 1.3mm, ( c ) 2mm, ( d ) 3mm, ( e ) 4mm, ( f ) 5mm. 4. Discussion ( e ) The results of the measurements made it possible to draw a number of conclusions. For a length of 0.7 mm, the paper fibers delaminated and crushed near the fixed lower handle of the machine. In this case, the ratio of the length of the sample to its thickness is L/g = 5. For lengths of 1.3 and 2.0 mm, destruction shall also occur near the lower handle with visible horizontal displacement of the samples. For these cases, we have L/g = 9.3 and L/g = 14.3, respectively. For the fastening lengths of 3.0 (L/g = 21.4) and 4.0 mm (L/g = 28.5), the destruction of the samples takes place in the central part and the sample takes the shape of the letter V. Note that paper edges enter tangentially into both handles. However, for a length of 5 mm (L/g = 35.7), the V-shape is very clearly visible, in particular the refraction itself. The sample at the places of attachment to both handles takes the shape as for joint-like support. In the theory of thin-walled structures, the following classification is assumed: when L/g > 25–30, where L is a smaller overall dimension, the plates are thin-walled; when 5 < L/g < 25 the plates are of medium thickness, while L/g ≤ 5 the plates are thick [16,17]. According to this classification, the clamping length L = 0.7 mm corresponds to thick plates, and for L = 1.3, 2.0, 3.0, 4.0 plates of medium length, and for L = 5.0 thin plate. For plates of medium thickness, modifications are made in relation to thin plates [18,25,26]. Figure 15 shows diagrams of changes in the deflection arrow of the sample as a function of displacement of the movable handle of the testing machine with the place where the maximum force is reached.

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Figure 15. Dependence of the value of the deflection arrow on the displacement of the movable handle at the fastening lengths: ( a ) 3mm, ( b ) 4mm, (c ) 5mm. The correctness of determining the deflection arrow using the developed image analy- sis technique was checked by comparing measured sample shortening with the analytically determined value using the formula given in [16]: Δ l = l ⎛ ⎝ 1 − 2 1 − 2 δ l 2 ⎞ ⎠ (3) where: l —sample length Δ l —sample shortening δ —deflection arrow. Figure 16 shows a comparison of the measured and theoretically calculated shortening of the paper sample with a clamping length of 4 mm and 5 mm as a function of its deflection. A slight difference between the measured and calculated values may result from the adopted destruction model, which does not reflect all the phenomena occurring during the test, or the inaccuracy of determining the deflection arrow by imaging methods.

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14

0.2

0.4

0.6

0.2

0.4

0.6

Deflection arrow, mm

Calculated

Measured

Calculated

Measured

( a )

( b )

Figure16. Comparison of the measured and theoretically calculated sample shortening during the test for clamping length of ( a ) 4mmand ( b ) 5mm.

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Figure 17 summarizes the diagrams of changes in the period of the sinusoidal function approximating the shape of the test sample as a function of displacement of the movable handle of the testing machine. Estimating the period until buckling occurs is not justified, since the shape of the edge of the sample does not resemble a sinusoid. From the moment the maximum force is reached, the value of the period stabilizes at a level comparable to the length of the fastening.

Figure 17. Dependence of the period of the sine wave modelling the shape of the sample on the displacement of the movable handle at the lengths of fastening: ( a ) 3mm, ( b ) 4mm, ( c ) 5mm. 5. Conclusions A measurement technique was developed, based on the simultaneous measurement of the dependence of the compressive force on the displacement of the movable handle of a universal testing machine and the recording of a series of images of a compressed sample of the tested material. This technique has a number of advantages over the traditional approach of recording only jaw movement and the force curve during the test. It enables non-contact measurement of the value of the deflection arrow of the sample during the test and gives the opportunity to observe its shape. This allows the shape of the tested paper samples to be modelled with different curves, e.g., a sinusoidal function. Thanks to this, it becomes possible to determine the relationship between the deflection arrow and other variables, e.g., force, displacement of the handle of the testing machine or work carried out on the sample. Visualization of changes in the shape of the sample in subsequent phases of the test together with the quantities measured using a universal testing machine facilitates the prediction of the model of destruction under given conditions and gives the possibility of its quantitative verification by determining the modelling error of the shape itself or the parameters determined on its basis. As an example of such a possibility, the effects of approximating the shape of the sample using the sinusoidal function and the error graph of this approximation allowing to estimate the limits of applicability of the proposed model are shown. The development of a model of paper destruction during compression is of great importance for predicting the strength properties of corrugated board and cardboard packaging produced from it. This will allow for savings in terms of packaging products in transport and reducing the consumption of paper raw materials for the production of cardboard. In order for the developed measurement technique to be fully useful in testing the strength properties of paper, the process of registration and pre-processing of sample images must be optimized. In particular, the procedure used to detect the optical edge of the sample does not allow for its correct detection in the vicinity of the attachment to

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the UTM holder. It is planned to mask the handle with black stickers. The authors are also looking for optimal image size settings, which will maximize the number of images recorded during the examination. Further research is also planned to develop an analytical model describing the phenomena occurring during paper compression and methods for determining the mechanism of paper destruction and the corresponding maximum force that destroys a paper sample. Author Contributions: Conceptualization, W.S.; methodology, W.S. and P.P.; software, P.P.; validation, P.P. and M.B.; formal analysis, Z.K.; investigation, Z.K.; resources, M.B.; data curation, M.B. and P.P.; writing—original draft preparation, P.P., Z.K. and W.S.; writing—review and editing, P.P., W.S., M.B. and Z.K.; visualization, P.P.; supervision, W.S.; project administration, W.S. All authors have read and

agreed to the published version of the manuscript. Funding: This research received no external funding. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable.

Data Availability Statement: The data presented in this study are available on request from the corresponding author. The data is not publicly available due to the high degree of complexity of their organization. The authors have not yet developed an appropriate standard for their storage. Conflicts of Interest: The authors declare no conflict of interest.

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PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® FROM THE PUBLISHERS OF PAPER TE Volume 9, Number 2, 2023

The value of data for environmental sustainability as perceived by the customers of a tissue-paper supplier PÄIVI LUOMA, 1 ROMANA RAUTER, 2 ESKO PENTTINEN, 3 & ANNE TOPPINEN 1 To manage their increasingly ambitious environmental agendas successfully, companies need better and more versatile data, yet the elements and mechanisms through which businesses and the environment benefit from data remain poorly understood. A single-case-study setting was designed for examining the perceived value of data for environmental sustainability as seen by the customers of a tissue-paper supplier. The findings, from material collected during interviews with customers in 2022, showcase the multifaceted nature of data's value for business operations and associated ability to support decisions and activities that encourage environment-informed choices and environmental improvements. Also, fully exploiting data's potential for environmental sustainability requires greater volume and detail of product-specific data, transparency of value chains and environmental impacts, and data's better management and sharing. The emerging insight related to the value of data strengthens understanding of how companies could, with data, support their customers' environmental performance. Contact information: 1 Department of Forest Sciences, University of Helsinki, Helsinki, Finland 2 University of Graz, Institute of Systems Sciences, Innovation and Sustainability Research, Graz, Austria 3 Department of Information and Service Management, Aalto University School of Business, Espoo, Finland Corp Soc Responsib Environ Manag. 2023;1 – 14. https://doi.org/10.1002/csr.2541 Creative Commons Attribution NonCommercial No Devis License

Article 2 – Tissue

Page 1 of 15

Received: 17 November 2022 Revised: 25 May 2023 Accepted: 27 May 2023 DOI: 10.1002/csr.2541

RESEARCH ARTICLE

The value of data for environmental sustainability as perceived by the customers of a tissue-paper supplier

Päivi Luoma 1

| Romana Rauter 2

| Esko Penttinen 3 | Anne Toppinen 1

1 Department of Forest Sciences, University of Helsinki, Helsinki, Finland 2 University of Graz, Institute of Systems Sciences, Innovation and Sustainability Research, Graz, Austria 3 Department of Information and Service Management, Aalto University School of Business, Espoo, Finland Correspondence Päivi Luoma, Department of Forest Sciences, University of Helsinki, Latokartanonkaari

Abstract To manage their increasingly ambitious environmental agendas successfully, companies need better and more versatile data, yet the elements and mechanisms through which businesses and the environment benefit from data remain poorly understood. A single-case-study setting was designed for examining the perceived value of data for environmental sustainability as seen by the customers of a tissue- paper supplier. The findings, from material collected during interviews with cus- tomers in 2022, showcase the multifaceted nature of data's value for business opera- tions and associated ability to support decisions and activities that encourage environment-informed choices and environmental improvements. Also, fully exploit- ing data's potential for environmental sustainability requires greater volume and detail of product-specific data, transparency of value chains and environmental impacts, and data's better management and sharing. The emerging insight related to the value of data strengthens understanding of how companies could, with data, sup- port their customers' environmental performance.

7, 00014 Helsinki, Finland. Email: paivi.luoma@helsinki.fi

Funding information The Metsämiesten Säätiö Foundation, Grant/Award Number: 21VE049KE; Kaute-säätiö, Grant/Award Number: 20220113

KEYWORDS customer value, environmental sustainability, forest industry, tissue paper, value of data

INTRODUCTION

These external pressures, in combination with the internally set objec- tives, call for companies' better management of their sustainability agendas by all means at their disposal, including versatile use of data to support setting the objectives, identifying improvement opportuni- ties, implementing appropriate actions, and seeing that objectives are met (Busch et al., 2022). In this connection, data on diverse aspects of business activities, service and product life cycles, and related environmental impacts can inform environment-linked sustainability efforts when the integration, discovery, and exploitation of said data (Miller, 2013) produce valu- able insight in support of environmental sustainability (Song et al., 2018). This is the case, for example, when data revealing the carbon footprint of a product are available and influence customers'

Companies have ambitious internal objectives for environment- related sustainability, connected with climate-change mitigation, cir- cular economy, and biodiversity protection. At the same time, they must contend with growing demands of external stakeholders for transparent and accountable activities (Comas Martí & Seifert, 2013). Customers desire traceability of products' value chains and evidence for the environment-related claims made (Rusch et al., 2022), and investors likewise ask for business transparency and data that attest to genuine environmental improvements and sustainability (Herzig & Schaltegger, 2006). Regulators, in turn, seek verified compliance and elimination of greenwashing (European Commission, 2020).

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2023 The Authors. Corporate Social Responsibility and Environmental Management published by ERP Environment and John Wiley & Sons Ltd.

Corp Soc Responsib Environ Manag. 2023;1 – 14.

wileyonlinelibrary.com/journal/csr

LUOMA ET AL .

via which data resources create value for environmental sustainability. Although research has pinpointed collaboration as crucial to any move toward sustainability, our review of pertinent literature identified no studies aimed at systematic understanding of how a company could, with the use of data, serve its customers' pursuit of their environmen- tal sustainability targets. In addition, there is a recognized need for further empirical research specifically geared to revealing how digital transformation supports reaching environmental goals (Beltrami et al., 2021; O'Rourke & Lollo, 2021; Rusch et al., 2022). The purpose behind this paper is to help fill that gap by examining data's value for environmental performance as perceived by the direct customers of a leading European tissue paper supplier. In a study from the perspective of environmental sustainability, we explored the terri- tory of customers' expectations/needs and how they are shifting. Set- ting out to uncover critical elements and mechanisms of data's value in this context, we addressed the following research question: How is the value of data for environmental sustainability perceived among busi- ness customers of a tissue paper supplier? We chose to focus on the value chain behind tissue paper because of its associated complex demands for environmental sus- tainability, from a range of stakeholders: customers, investors, regula- tors, and others (Ghosal, 2015; Toppinen et al., 2017). These demands cast the rapidly growing need for environmental-performance-related data into high relief also. The body of data required comprises myriad details that a company may collect, produce, process, and share in relation to its activities, products, and value chains (all the way through to customers and disposal) that could shed light on their envi- ronmental impacts and the improvement opportunities. In previous lit- erature on the forest companies (Mäkelä, 2017) it is found that these companies report on the environmental performance of their supply chain only very little. Hence, relying on secondary sources available in reporting data from the companies themselves is not likely to produce sufficiently in-depth insights from the customer interface to facilitate solid analysis, calling for collection of primary data. The case company, Metsä Tissue, had recognized a need to make better use of data to enhance its environment-related performance in the business of tissue-paper manufacture, and it sought to understand how, alongside its customers, it could enhance its utilization of data for environmental sustainability. The findings presented here are output from a joint pro- ject with Metsä Tissue carried out in January to June 2022 that included eight interviews with direct customers of Metsä Tissue engaged in retail and professional sales. This empirically underpinned study's contribution to theory is twofold. First, we identified the discrete elements of the environmen- tal sustainability value that customers perceive in data, and, second, our work makes the multifaceted nature of data's value in support of environment-informed decisions and environmental improvements explicit. The resulting sense of the value held by data content and the possible uses points to the necessity of reliable product-specific and environment-related data to support better informed decisions within companies and along their value chains. The work's central contribu- tion to practice is in strengthening our understanding of how compa- nies could seize data's power to enhance their customers'

purchase decisions (Pinheiro et al., 2022; Rusch et al., 2022). Other examples involve data sharing between suppliers and customers; for instance, detailing the content and origin of the product can help all parties understand and manage potential biodiversity issues and other environmental risks along the supply chain (Contador et al., 2021). In addition, companies need data for proving their environmental perfor- mance to customers, investors, and regulators who demand evidence of progress on clearly defined pathways to significant reduction in greenhouse-gas emissions and who require compliance with the EU's new Corporate Sustainability Reporting Directive (Science Based Tar- gets Initiative, n.d.; European Commission, 2021). When cultivated into information and, further, into knowledge, data can support better, more environment-aware decisions by incumbent companies and by their customers and suppliers. The intersection of environmental sustainability and digital trans- formation, encompassing increasing availability and utilization of data, has recently captured scholars' more intense interest (see, e.g., Bai et al., 2020; Cardinali & De Giovanni, 2022). Digitalization and related data are now recognized as gateways to supporting climate-change mitigation, circular economy, and other environment-linked goals (Di Maria et al., 2022; George et al., 2021; Liu et al., 2022), with gen- eral discussion pointing to their potential role in a shift toward sustainability – reduced resource-intensity, greater energy-efficiency, waste reductions, and decreased CO 2 emissions (e.g., Chiarini, 2021; Kerin & Pham, 2020; Niehoff, 2022). Specific digital technologies facilitating activities such as collection and utilization of data, along- side the so-called Industry 4.0 in general, are recognized as prospec- tive means of supporting more sustainable business strategies that incorporate new business models, manufacturing practices, and supply-chain solutions (de Sousa et al., 2018; Gupta et al., 2021). Making data-driven decisions is increasingly relevant not only in companies' internal activities but also in their larger value chains, bringing in suppliers and customers (Dubey et al., 2019; Gebhardt et al., 2021; Gold et al., 2010). Data needs are growing more precisely elucidated, and greater detail is required – the data must cover numerous facets of product life cycles and value networks. These requirements necessitate considerable expansion in the quantities of data needed but also emphasize the requisite of successfully manag- ing and utilizing the data (Gandolfo & Lupi, 2021). Thus far, though, potentially valuable environmental sustainability data have remained scattered and under-utilized (Rusch et al., 2022). Efficient means of collecting, managing, and utilizing said data in business decision- making are still emerging, and common definitions, methods, and rules of the game for utilizing and sharing data are largely absent (Busch et al., 2022; Elias Mota et al., 2020). In this context, the value that versatile product life-cycle and value-network data offer for realizing environmental gains is poorly understood, and companies lack understanding of the data's ultimate value for businesses and their customers. These shortcomings render it difficult to prioritize data-linked development needs and articulate cases for investing in related innovation and capability development. It is difficult even to point to empirical foundations, since little research has examined the details of the elements and mechanisms

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