Life cycle analysis (LCA) is a popular tool for determining the environmental impacts of a product in use. The aim of this study is to carry out a life cycle analysis, gate-to-gate, of a mass packaging process using a polyethylene shrinking film with a focus on energy consumption, raw material use and associated emissions, and film post-consumer disposal scenarios. Two different scenarios for the disposal of the shrinking film used in the packaging process were analyzed, namely recycling and landfills. The analysis showed that choosing recycling as the post-consumer management of film waste within the studied system boundaries reduces the negative environmental impact by approximately 17%. The study showed significantly higher environmental benefits in terms of harmfulness to human health for recycling than for landfills. A study of the environmental impact of the mass packaging process depending on the energy source showed that using a renewable source minimizes environmental damage. Three sources of energy options were analyzed, including the country’s energy mix, wind, and solar. The research shows that changing sources to wind power reduces potential damage to human health by 91%, to ecosystems by 89%, and to resources by 92% compared to the country’s energy mix power option. When comparing the results for the renewable energy options, the variant with energy from wind presents lower harm in all three damage categories compared to the solar option.

YyTo date, a large number of finite element methods have been developed to study the dynamics of shell structures. Most of them are generally based on the degenerated solid approach and other less in shell theories, but introducing, in this last case, some assumptions to analyze this problem: some of them refer to shallow shells (slightly curved shells), or consider thin shells neglecting shear deformation, or dispense some terms in their stress-strain developments like the off-diagonal components of the curvature or metric tensors (orthogonal coordinates). In the present work, we present an improved finite element method for the linear dynamic analysis of shells, from thin to moderately thick and thick shells, developed in general curvilinear coordinates, based on a refined shear deformation shell theory and free of the well-known shear locking effect. Exact constitutive equations, including higher order moments-strains relations, are also deduced for the adequate analysis of thick shells. To circumvent the shear locking problems, the mixed interpolation of the tensorial components (MITC) of the linear strain tensor is used. An exhaustive study of different surfaces is performed, especially in doubly curved shells, and interesting conclusions of the higher order modes of vibration and the strain energy of the element are derived. Other desirable features like a low computational effort, a straightforward extension to nonlinear formulation and applications for composite shells are found in this novel and general formulation. Very good results in the proposed practical cases have been found.

The aim of this study was to assess the environmental impact of using recycled polyethylene film for shrink-wrapping bottles. For this aim, film properties were tested and the harmfulness of the packaging process was simulated for film made from virgin and recycled material. For the recycled film, the results showed an increase of 14.7% in impact resistance, a change from −21.6 to +94.3% in tear resistance, and a decrease of up to 45.4% in tensile strength in dependence on the test direction. Using differential scanning calorimetry (DSC), the changes in the properties of the two types of film with temperature changes were evaluated. DSC analysis showed that recycled film has a 1.94 °C lower glass transition temperature and a 1.85 °C lower melting point in comparison to polyethylene film. This can reduce the temperature of the packaging process and lead to energy savings. A study conducted with SimaPro 9.3 software showed that a change in films made of virgin raw material to recycled films reduces the negative impact on the environment from 68.5 to 11.5%. The change also reduces resource consumption by about 80 percent. The results of conducted tests and simulations showed that using recycled film for bottle packaging allows reducing the negative environmental impact of examined process, especially in terms of resource consumption and energy savings.

This paper describes a new Web portal offering experimental labs for ubiquitous training of university engineering students in work-related risk prevention. The Web-accessible computer program simulates the noise and machine vibrations met in the work environment, in a series of virtual laboratories that mimic an actual laboratory and provide the corresponding calculations and plots. The main goal of this work is to provide new learning strategies and methodologies to motivate students and challenge them to learn risk prevention strategies for the workplace. Students can perform the virtual experiments before taking their actual laboratory classes and repeat them whenever and as often as they want. Evaluation results show the system was considered very satisfactory, with an average student rating of 8.95 out of a maximum of 10. As well as being used for educational purposes, the program can be used in industry as a decision tool for factory workers and technicians.

Three-dimensionally printed parts are increasingly used in industry for quick repairs. They are often operated in the presence of grease, oil, and others. This article describes the effect of engine mineral oil on the fatigue life of 3D-printed FDM plastic samples. For this reason, this article aimed to investigate the influence of oil on the fatigue life of materials made using this technology. Samples made of ABA, ASA, PLA, and HIPS materials were printed with 100% fill. Divided into groups, they were stored for 15, 30, and 60 days in an oil bath at a room temperature of 23 °C and an increased temperature of 70 °C. To compare the effect of storage in oil, static tests were performed to determine the tensile strength of the specimens and to determine the load levels for the cyclic tests. Cyclic tests were performed to determine the effect of oil and temperature on the fatigue life. Internal structure studies of the specimens were performed using computed microtomography to determine the changes in the porosity of the specimens under the influence of oil. In the case of ABS, the oil-bathed samples showed a clear increase in the fatigue life, especially at 23 °C. For the ASA specimens, an increase was also evident, especially for the lower stress value. For HIPS and PLA, no clear effect of the oil bath on the fatigue life value of the samples was determined. Porosity studies using computed microtomography showed a clear decrease in the porosity of the samples as a result of the oil bath for all of them.

In this work, new equations for first-order shear deformation plates are deduced taking into account the kinematic assumptions of the Bolle-Reissner theory but considering the equilibrium equations in the deformed configuration for the plate. The system of differential equations deduced is applicable to the calculation of the stresses in isotropic plates and is valid for thin and moderately thick plates. Analytical solutions are also presented in this work which are compared, when possible, with the ones obtained with other refined shear deformation plate theories.