The thermal decomposition of corrugated cardboard has been studied in inert and oxidative (non-flaming) atmospheres under a range of radiant heat fluxes relevant to fire conditions in warehouse ...storage applications. Experiments were performed in a Fire Propagation Apparatus (FPA) on double-wall corrugated cardboard at heat flux levels of 20, 60, and 100kW/m2. Pyrolysis data comprised of gasification rates and surface temperatures were collected for tests carried out in ambient atmospheres consisting of 100% N2 as well as 2%, 6%, 8%, 10%, and 14% (mol) O2 in balance nitrogen. It is shown that the presence of oxygen has an appreciable effect at all heat flux levels; however, it is most prevalent at low heat fluxes. Analyses are presented in an effort to gain further understanding of char oxidation processes. Results show that the maximum heat evolved in oxidative environments is relatively constant and similar for all conditions tested. Furthermore this heat release rate is found to be comparatively small relative to the high radiant fluxes tested; this explains the experimentally observed behavior. This study provides a comprehensive dataset that may be used in conjunction with approaches recently adopted in the fire community in which optimization procedures are employed to generate material properties for pyrolysis models used in CFD fire simulations.
Numerical homogenization is an excellent tool for the quick simplification of complex structures with a model that is much simpler and, at the same time, accurately reflects the mechanical behavior ...of the original model. Corrugated cardboard modeling, with all geometrical nuances preserved, is a complicated and time-consuming process. The transfer of a full 3D model of corrugated board composed of two flat layers and a corrugated middle layer to one layer only, with substitute elastic parameters, greatly simplifies this process. Because the individual layers of corrugated cardboard are made of paper with a grammage in the range of 80–200 g/m2, i.e., very thin plates, they are slightly buckled even in the initial configuration. These imperfections affect the equivalent parameters that are obtained in the homogenization process. This paper presents an approach of taking into account these imperfections when creating a simplified model. The numerical homogenization method based on the equivalence of elastic energy between a representative volumetric element (i.e., a part of a full 3D model) and an equivalent plate were applied. Different shapes of imperfections were analyzed in order to account for the buckling modes, notably for a specific unit deformation and curvature. Finally, one form of initial imperfections was proposed, which most accurately reflects the decrease in all plate stiffnesses.
Corrugated cardboard is an ecological material, mainly because, in addition to virgin cellulose fibers also the fibers recovered during recycling process are used in its production. However, the use ...of recycled fibers causes slight deterioration of the mechanical properties of the corrugated board. In addition, converting processes such as printing, die-cutting, lamination, etc. cause micro-damage in the corrugated cardboard layers. In this work, the focus is precisely on the crushing of corrugated cardboard. A series of laboratory experiments were conducted, in which the different types of single-walled corrugated cardboards were pressed in a fully controlled manner to check the impact of the crush on the basic material parameters. The amount of crushing (with a precision of 10 micrometers) was controlled by a precise FEMat device, for crushing the corrugated board in the range from 10 to 70% of its original thickness. In this study, the influence of crushing on bending, twisting and shear stiffness as well as a residual thickness and edge crush resistance of corrugated board was investigated. Then, a procedure based on a numerical homogenization, taking into account a partial delamination in the corrugated layers to determine the degraded material stiffness was proposed. Finally, using the empirical-numerical method, a simplified calculation model of corrugated cardboard was derived, which satisfactorily reflects the experimental results.
Carbon aerogel (CA
Sol-Ads
) was prepared from waste corrugated cardboard (WCC) by using a green and facile strategy and it was explored as an all-in-one solar evaporator and a floatable absorbent. ...Thermal conversion of carbon precursor was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer. The amorphous carbon aerogel was made up of criss-crossing carbon ribbons and it had a typical micromesoporous structure and a specific surface area of 575 m
2
g
−1
. It exhibited remarkable optical absorption over 81.8% in the UV and Vis regions and over 70% in the NIR region. The surface temperature of dry CA
Sol-Ads
can achieve 77.9 °C under 1 kW m
−2
irradiation. The hydrophilic 3D network structure of CA
Sol-Ads
provides a large volume for the storage of liquids; thus, the carbon aerogel was able to store as much as 13.4 times its own weight in water. Solar-driven evaporation rate over CA
Sol-Ads
saturated with water was calculated to be 1.68 kg m
−
2
h
−1
, which was 4.5 times the value achieved with bare water under 1 kW m
−2
irradiation. The adsorption behavior of CA
Sol-Ads
for methylene blue (MB) fitted the Langmuir isotherm model with the maximum monolayer adsorption capacity of 108 mg g
−1
. The monolithic CA
Sol-Ads
can be used as a self-floating absorbent for the adsorption of MB from water, and the adsorption kinetics followed pseudo-second-order kinetics model.
Three-dimensional carbon aerogel (CA800) was prepared from waste corrugated cardboard (WCC) by the procedure of slurrying, solvent replacement, drying, and carbonization in turn, and the product was ...explored as an all-in-one evaporator for solar steam generation without bulk water. Carbonization of the precursor was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer. Results showed that CO
2
, CO, furfural, and levoglucosan were released during pyrolysis of WCC within the range of 300 to 390 °C, while polymerization of newly formed char between 390 and 580 °C mainly resulted in the formation of CO
2
and CO. Both pyrolysis and polymerization reactions can be described by diffusion-controlled mechanisms, and the activation energies were 155.62 and 11.17 kJ mol
−1
, respectively. CA800 possessed a BET surface area of 210 m
2
g
−1
. Light can be effectively absorbed and converted into heat by CA800, and its surface temperature achieving 73 °C under 1 kW m
−2
irradiation. CA800 had outstanding wettability due to the presence of hydrophilic minerals in carbon matrix, and it was able to store as much as 15 times its own weight in water due to its abundant interconnected channels and hierarchical nanopores. Solar-driven water evaporation rate over CA800 achieved 1.72 kg m
−2
(normalized to projection area), which was nearly 6 times higher than the value achieved by the bare water system. The photothermal conversion efficiency was calculated to be 118 %, and the overestimated efficiency was caused by the environmental energy gained by the cold evaporation surface of CA800.
During a product's entire life cycle the significance of packaging varies in terms of environmental impacts. From the perspective of companies which manufacture packaging or packaging has an ...important role in their value chain it can be a relevant issue to focus on in their efforts to improve the environmental performance of their activities. The aim of this study was to compare the life cycle environmental impacts of a real product (bread) delivery system using either reusable HPDE plastic crates or recyclable corrugated cardboard (CCB) boxes for product transportation. In this paper we focused on the delivery systems (not the delivered product) covering the manufacturing of the crates/boxes, their use, the delivery routes from bakery to retailers and waste management/recycling of the crates/boxes. As a result we concluded that the recyclable CCB box system was a more environmentally friendly option than the reusable HPDE plastic crate system in all the studied impact categories based on the defined boundaries and assumptions. Transportation played a very important role in the environmental impacts of the analysed systems. Therefore, changes, e.g. in the weights of products and their secondary packaging or the transportation distances could affect the results considerably.
•CCB box system is a more environmentally friendly option than Plastic Crate system.•Container material does not alone define impacts of the delivery system.•Within efficient recycling a recycled product can perform better than reusable one.•Transportation played the most important role in the impacts of the systems.
In the modern packaging industry, a large assortment of materials, various technologies and equipment is used. Market relations form the demand for inexpensive and optimal in terms of its operational ...and functional properties, qualitative, environmentally friendly packaging. The analysis of compliance with these requirements allowed prioritizing the packages of laminated micro-corrugated cardboard as a promising way of making them in the modern market. The application of the lamination process extends the design and range of such packages. Important in this production chain is quality offset printing, the choice of cardboard for printing, micro-corrugated cardboard and adhesives for lamination, taking into account their technological and operational characteristics. The reproductive and graphic indicators of liners printed by offset printing are investigated in this work. It was considered the process of their laminating to micro-corrugated cardboard using the adhesive device of a new construction with the further determination of the operational parameters of the packaging material. As a result of the research, graphic dependencies were constructed that allow us to assess the quality reproduction of a color image in the offset printing and the operational stability of laminated micro-corrugated cardboard. The conducted experimental researches allowed establishing the dependence of the strength characteristics of laminated micro-corrugated cardboard on the technological parameters of the process of lamination.
As part of a study of the combustion of boxes of commodities, rates of upward flame spread during early-stage burning were observed during experiments on wide samples of corrugated cardboard. The ...rate of spread of the flame front, defined by the burning pyrolysis region, was determined by visually averaging the pyrolysis front position across the fuel surface. The resulting best fit produced a power-law progression of the pyrolysis front,
x
p
=
At
n
, where
x
p
is the average height of the pyrolysis front at time
t,
n
=
3/2, and
A is a constant. This result corresponds to a slower acceleration than was obtained in previous measurements and theories (e.g.
n
=
2), an observation which suggests that development of an alternative description of the upward flame spread rate over wide, inhomogeneous materials may be worth studying for applications such as warehouse fires. Based upon the experimental results and overall conservation principles it is hypothesized that the non-homogeneity of the cardboard helped to reduce the acceleration of the upward spread rates by physically disrupting flow in the boundary layer close to the vertical surface and thereby modifying heating rates of the solid fuel above the pyrolysis region. As a result of this phenomena, a distinct difference was observed between scalings of peak flame heights, or maximum “flame tip” measurements and the average location of the flame. The results yield alternative scalings that may be better applicable to some situations encountered in practice in warehouse fires.
In this paper, an analytical homogenization model for corrugated cardboard and its numerical implementation in a shell element are presented. Taking into account the geometric and mechanical ...properties of the corrugated board components, this homogenization model leads to an elastic stiffness matrix relative to the generalized strains and internal efforts for an equivalent orthotropic plate. Special attentions are paid to the corrugated cardboard behaviours under the transverse shear efforts and torsion moments. Both laminated and sandwich plate theories are studied and some important improvements are proposed. This model is then implemented into a 3-node shell element called T3γ18 for the linear and buckling analyses. The results obtained by the present model are compared to those given by 3D shell simulations and experiments. The comparison shows the efficiency and accuracy of our homogenization model.
Finite element analysis (FEA) has been proven as a useful design tool to model corrugated paperboard boxes, and is capable of accurately predicting load capacity. The in-plane deformation, however, ...is usually significantly underpredicted. To investigate this discrepancy, a panel compression test jig, that implemented simply supported boundary conditions, was built to test individual panels. The panels were then modelled using non-linear FEA with a linear material model. The results show that the in-plane deformation was still underpredicted, but a general improvement was seen. Three discrepancies were identified. The first was that the panels showed an initial region of low stiffness that was not present in the FEA results. This was attributed to imperfections in the panels and jig. Secondly, the experimental results reported a lower stiffness than the FEA. Applying an initial imperfection in the shape of the first buckling mode shape was found to reduce the FEA stiffness. Thirdly, the panels showed a decrease in stiffness near failure, which was not seen in the FEA. A bi-linear material model was investigated and holds the potential to improve the results. Box compression tests were performed on a Regular Slotted Container (RSC) with the same dimensions as the tested panel. The box displaced 13.1 mm compared to 3.5 mm for the panel. There was an initial region of low stiffness, which accounted for 7 mm of displacement compared to 0.5 mm for the panels. Thus, box complexities such as horizontal creases should be included in finite element (FE) models to accurately predict the in-plane deformation, while a bi-linear (or any other non-linear) material model may be useful for panel compression.
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