Analytical Determination of the Bending Stiffness of a Five-Layer Corrugated Cardboard with Imperfections

Bending stiffness (BS) is one of the two most important mechanical parameters of corrugated board. The second is edge crush resistance (ECT). Both are used in many analytical formulas to assess the load capacity of corrugated cardboard packaging. Therefore, the correct determination of bending stiffness is crucial in the design of corrugated board structures. This paper focuses on the analytical determination of BS based on the known parameters of the constituent papers and the geometry of the corrugated layers. The work analyzes in detail the dependence of the bending stiffness of an asymmetric, five-layer corrugated cardboard on the sample arrangement. A specimen bent so that the layers on the lower wave side are compressed has approximately 10% higher stiffness value. This is due to imperfections, which are particularly important in the case of compression of very thin liners. The study showed that imperfection at the level of a few microns causes noticeable drops in bending stiffness. The method has also been validated by means of experimental data from the literature and simple numerical finite element model (FEM). The obtained compliance of the computational model with the experimental model is very satisfactory. The work also included a critical discussion of the already published data and observations of other scientists in the field.

Bradysia aff. impatiens and Bradysia aff. ocellaris in the semi-hydroponic strawberry production system in Southern Brazil

ABSTRACT: Soilless cultivation of strawberry is in expansion in Brazil due to factors like the reduction of phytosanitary problems and the possibility of extending the crop period, as well as the ergonometric facility for management of the culture. However, black fungus gnats (Sciaridae, Diptera) are ubiquitous pests in the greenhouse production system, causing direct and indirect damage to plants. ThIS study evaluated the occurrence of black fungus gnats species in semi-hydroponic cultivation of strawberry and to identify the species, as well as to describe the symptoms in infested plants. The research was developed in commercial productions of strawberry, in five municipalities (Arroio do Padre, Canguçu, Capão do Leão, Pelotas and Turuçu) during July to December 2017, where adult samples were collected twice a month, with petri dish traps containing water and neutral detergent placed inside the greenhouses between the plants. A total of 2030 adult gnats belonging to two species were collected. Bradysia aff. impatiens, accounted with 90.79% of the total, and Bradysia aff. ocellaris, accounted with 9.21%. In order to assist the correct determination of species, males of both species were identified and illustrated. With respect to the symptoms observed during the research, it was possible to verify since the wilted crown of plants to the death of plants, which were confirmed by the presence of larvae in the root system. As the occurrence of these insects is recent in strawberry, there is no pesticide registered in Brazil, so management strategies (cultural, physical, and sanitary) also are discussed.

On the energy gap determination of organic optoelectronic materials: the case of porphyrin derivatives

A correct determination of the ionization potential (IP) and electron affinity (EA) as wells as the energy gap is essential to properly characterize a series of key phenomena related to...

Charge transfer state characterization and voltage losses of organic solar cells

A correct determination of voltage losses is crucial for the development of organic solar cells with improved performance. This requires an in-depth understanding of the properties of interfacial charge transfer (CT) states, which not only set the upper limit for the open-circuit voltage of a system, but also govern radiative and non-radiative recombination processes. Over the last decade, different approaches have emerged to classify voltage losses in organic solar cells that rely on a generic detailed balance approach or additionally include CT state parameters that are specific to organic solar cells. In the latter case, a correct determination of CT state properties is paramount. In this work, we summarize the different frameworks used today to calculate voltage losses and provide an in-depth discussion of the currently most important models used to characterize CT state properties from absorption and emission data of organic thin films and solar cells. We also address practical concerns during the data recording, analysis, and fitting process. Departing from the classical two-state Marcus theory approach, we discuss the importance of quantized molecular vibrations and energetic hybridization effects in organic donor-acceptor systems with the goal to providing the reader with a detailed understanding of when each model is most appropriate.

Determination of gushing potential of barley

A new control method for the determination of the malting barley susceptibility to gushing was developed. The method is based on the modified Carlsberg test (MCT) after prior stimulation of barley with substances that promote the germination process. Barleys from the harvest of 2020 and malts produced from them were used to develop and verify the method. The selection of barleys was based on the results of gushing potential detected in the produced malts. To optimise and verify the method, the barley variety Sunshine with a high gushing potential of both barley (139±33 g) and malt (144±13 g), and the barley variety Pionier with zero gushing potential of both barley and malt were used. Malt was produced from the Lodestar barley variety with a high content of the mycotoxin deoxynivalenol. Gushing of the malt was 127±10 g. The gushing potential in barley was determined by the MCT method after prior stimulation of germination. For comparison, the gushing potential was also determined by the MCT method without stimulation of germination. It was proved that stimulation of germination is a key process for correct determination of the susceptibility of barley to gushing. The newly developed method was used for the determination of the gushing potential of five barleys from the harvests of 2020 and 2021. Control gushing determination of five malt samples was performed using the MCT method. An agreement between the measured data was found.

Detection of periodic displacements of shell structures with edges using spline surfaces, meshes and point clouds

This research paper tackles the problem of determining displacements of complex-shaped shell structures, measured periodically using laser scanning. Point clouds obtained during different measurement epochs can be compared with each other directly or they can be converted into continuous models in the form of a triangle mesh or smooth patches (spline functions). The accuracy of the direct comparison of point clouds depends on the scanning density, while the accuracy of comparing the point cloud to the model depends on approximation errors that are formed during its creation. Modelling using triangle meshes flattens the local structure of the object compared to the spline model. However, if the shell has edges in its structure, their exact representation by spline models is impossible due to the undulations of functions along them. Edges can also be distorted by the mesh model by their chamfering with transverse triangles. These types of surface modelling errors can lead to the generation of pseudo-deformation of the structure, which is difficult to distinguish from real deformation. In order to assess the possibility of correct determination of deformation using the above-mentioned methods, laser scanning of a complex shell structure in two epochs was performed. Then, modelling and comparison of the results of periodic measurements were carried out. As a result of the research, advantages and disadvantages of each method were identified. It was noticed that none of the methods made it possible to correctly represent all deformations while suppressing pseudo-deformation. However, the combination of their best qualities made it possible to determine the actual deformation of the structure.

Determination of temperature gradient of slender structure

This study investigates convenient methods of determination of temperature gradient of slender structures in time. Correct determination of temperature along the height of the cross-section takes a key role in defining the temperature loading of slender bridge structures. A proper definition of temperature loading is crucial for structures such as stress ribbon because of their sensitivity to temperature change in terms of geometrical changes of the structure. Correct determination of the temperature gradient is important during long-term geodetic monitoring, which might be used to prove the correctness of computational models of bridge structures. To approximate heat transfer in cross-section, a test specimen with temperature sensors installed along the height was formed and continuously monitored. The accuracy of the retrofitted temperature sensors was also investigated. The temperature at the surface of the specimen, solar radiation and wind velocity were used as input data for heat transfer analysis. The measured values from sensors situated along the height were subsequently used for verification of performed heat transfer analysis on volume computational model in the software Ansys Mechanical.

Selection of a method for calculating heat gain from solar radiation to determine the load on the climate system of the cabin of a mobile car

Introduction. The article analyzes and selects the most rational methods for calculating the heat gain from solar radiation. The correct calculation of this component of the heat balance allows you to correctly determine the power of the projected cabin climate system, which will ensure optimal working conditions at the workplace of mobile car operators. Problem Statement. The objective of this study is to analyze and select a rational method for calculating heat gain from solar radiation for the correct determination of the thermal load on the climate system of the cabin of a mobile car. Theoretical Part. To implement the task, the most common methods for calculating solar radiation were described and analyzed in detail and the most accurate ones were recommended. Conclusions. The more labor-intensive method of V.N. Bogoslovskiy (taking into account the time of day) can be recommended for automated calculations in Excel, and the method of P.Y. Gamburg (taking into account the sides of the horizon) — for comparative estimated engineering calculations. When conducting "in-depth" model calculations and accounting for solar radiation, the ASHRAE method is explicitly suitable, which has two important advantages: it takes into account the solar factor in relation to a specific type of glazing and is adapted for automated calculations in ANSYS FLUENT.

Some directions of improvement of ways of interpretation of procedural administrative-tort legal norms of the customs legislation

Having studied the peculiarities of interpretation of administrative-tort provisions of customs legislation establishing the procedure for proceedings on violations of customs rules, the author, in particular, expresses the opinion that in order to ensure the legality and validity of the decision to impose administrative penalties through the correct determination of the circumstances of the case and the applicable law as well as through the choice of a fair type and amount of administrative penalty – the customs legislation on the right to explain the alleged offense and comment on the case should be interpreted in a way that the person prosecuted should be given sufficient time and procedural opportunities to express their position on the legal substantiation of the allegation that they committed an offense and on the proposed penalty, as well as to provide evidence on the circumstances of the case. Also, the author substantiates that the model of termination of proceedings in customs rules violation case on the basis of a compromise, introduced in the customs legislation, needs to be radically improved, because it is built so that this tool of customs administration does not correspond to its nature and purpose since under the current customs law this model demands unconditional admission of guilt and imposition of possible type and amount of administrative penalty, which is unchangeable according to negotiated mutual concessions. Moreover, the motivation of offenders to conclude amicable agreements with customs authorities is limited to avoiding stricter penalties for repeated offenses, which is incompatible with the principle of inevitability of liability and may devalue the progressive increase in penalties. In addition, the author proposes ways to expand the interpretation of customs law on the temporary seizure of goods, vehicles and documents to maximize the protection of property rights of enterprises, which in light of the circumstances may be unreasonable and disproportionate.

The debate concerning the origin of the Whin Sill of northeast England during the early and mid-19th century

The term sill nowadays employed for a broadly concordant igneous intrusion is widely believed to have been derived from the local term for persistent hard beds in the Carboniferous sequence of Northeast England, in particular the Whin Sill. Despite the intrusive origin of the Whin having been demonstrated in Teesdale by Sedgwick in 1827, for much of the 19th Century the alternative extrusive hypothesis, of which Phillips (1836) was the principal proponent, was widely favoured. There were three principal reasons why the intrusive origin was not more widely held, unquestioning acceptance of the erroneous belief of local miners that the Whin Sill was always at the same stratigraphical horizon, a perception that the Teesdale outcrops were not necessarily typical of the rest of the region and a reluctance to accept that the intrusion of such large volumes of magma over such a great area was physically possible. In the 1870s, first the work of Tate and then the detailed six-inch to one-mile mapping of the Geological Survey finally dispelled any notion that the sill was at a consistent stratigraphical level. Curiously, though the correct determination of the intrusive origin of the Whin Sill was one of Sedgwick's earliest and greatest achievements in Northern England, it was not deemed of sufficient importance to merit mention by his biographers.