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Numerical assessment of hydroelastic effects in water impact experiments with pseudo-rigid impactors
Get PDFWhat are the growth benefits of watering cherry tomatoes with acidic teas?
No full textCherry tomatoes have a short growth cycle consisting of three phases: growth, flowering, and fruiting. In this study, cherry tomatoes were watered using water and three different teas with varying acidities—chamomile tea, green tea, and black tea. Previous studies typically focused on tomato growth in controlled environments with consistent pH levels. They often aimed to maintain the appropriate pH in soil for plants that thrive in acidic or basic soils, rather than neutral ones. However, this experiment aimed to explore the use of tea to alter soil pH for more effective tomato growth. While there exist numerous studies on acidic teas, this research consolidated their effects into a single study. The experiment involved 40 pots organized into groups of 10, each receiving one of the three teas or water. Soil was filled in these pots, and 7 germinated seeds were planted in each pot, followed by daily watering with 20 mL of the designated liquid. Throughout the study, soil pH levels remained stable across the different groups tested, suggesting that the primary factor influencing variations in leaf yield and plant height was gallic acid. However, the findings regarding plant height and leaf production were statistically not significant. Future work will involve analyzing different teas with diverse properties to expand understanding in this area. 
Bridge damage detection by variational mode decomposition and PCA of traffic-induced vibrations under environmental variability
Get PDFLife cycle assessment of new Talgo lightweight prototypes
No full textThe European rail network is largely electrified, and rail emits far less CO2 than equivalent travel by road or air. It accounts for only 0.4 % greenhouse gas emissions from EU transport, while all EU transport accounts for 25% of the EU’s total emissions. Additionally, rail is the only transport that between 1990 and 2017 has consistently reduced its emissions and energy consumption, while increasingly using renewable energy sources.
Following this green line, this article presents the Life Cycle Assessment (LCA) study of new generation trains, mainly based on lightweighted primary structures made of composite material (about 30-50% weight loss compared to conventional ones).
The composite materials are novelty in the railway sector. Their introduction brings a clear advantage from the point of view of train capacity or energy/infrastructure canon savings. However, it needs to be justified from the LCA point of view.
Two different stages are developed in this article. An LCA of the new prototypes (production, assembly, transport and use phase). It is completed with an LCA of conventional structures. The second phase presents a comparison between the environmental impact produce using CFRP materials or metallic materials at the end of a useful life (EoL) of a carbody.
The results indicates that, at EoL, the composite material would be more economically and environmentally attractive than the current materials
Elastomeric composite materials reinforced with natural fibers and with self-healing capacity
No full textElastomeric composite materials are widely used in multiple applications, especially in the automotive industry; however, they have the drawback of being difficult to recycle, generating a significant environmental impact. For this reason, in recent years there has been an increase in research for the development of self-healing and biodegradable materials that minimize this impact by extending their lifetime. In this context, the aim of this work is to design a new generation of self-healing elastomeric composite materials using additives of natural origin. For this, epoxidized natural rubber (ENR) and cellulose propionate (CP) were used as matrix, reinforced with cellulose fibers. Self-healing was achieved by combining the flow of the thermoplastic (CP) phase (extrinsic mechanism) and the formation of hydrogen bonds between the ENR and the CP (intrinsic mechanism). A promising repair efficiency of 95% was obtained, as well as an increase in tensile strength in the presence of cellulose fibers, without affecting the healing capacity of the material. Therefore, this work overcomes the well-known dichotomy between mechanical performance and self-healing and constitutes a new contribution in the field of self-healing elastomeric composites using bio-based additives
Italian Dams Bibliography
No full textRASSEGNA BIBLIOGRAFICA DELLA LETTERATURA ITALIANA SULLE DIGHE DI RITENUT
Application of high-dimensional multi-objective differential evolutionary algorithm based on global ordering to heat supply pipe network resistance identification
No full textThe distribution of resistance coefficients of heat supply pipe networks is the key data guiding the hydraulic balance adjustment of heat networks. Since the heat supply pipe network is composed of many pipe segments and the resistance coefficient of each pipe segment is different during heat supply operation, the identification of the resistance coefficient of the heat supply pipe network is an optimization problem with multiple objective functions. In this paper, a high-dimensional multi-objective differential evolutionary algorithm based on global sorting is developed as a method to identify the resistance coefficients of the heat network and the multi-objective algorithm is applied to the resistance identification of the heat network, and the computational process of resistance identification is improved. The fuzzy mathematical method is applied to the process of resistance identification, and a set of optimal solution sets are generated through the identification of each pipe segment and the optimal solutions are selected from the optimal solution sets based on the fuzzy degree of subordination to solve the problem of determining the optimal solutions. The problem of determining the optimal solution is solved. The results show that compared with the single-objective algorithm, the high-dimensional multi-objective differential evolutionary algorithm based on global sorting produces a uniform and concentrated optimal solution set, and the optimal solution accuracy is higher
ROBUSTNESS AND CONSEQUENCE BASED ASSESSMENT OF AN EXISTING DAM
Get PDFRobustness plays a relevant role in the capacity of a structure to sustain abnormal loads
or to deal with unexpected events with large effects, such as explosions and terroristic
attacks. Such situations on dams may have extremely large consequences. For buildings,
the design approach that best implements robustness concepts is represented by the so
called “Consequence Based Design”: even if nothing is known about the cause, selective
element removals and extreme load on the structure are modeled, and their effects are
determined with respect to progressive collapse and damage arrest.
In the paper we try to set-up a “Consequence Based Assessment” of a typical example of
a gravity dam built between the ‘30s and ‘40s of the last century in the northwestern
Italian Alps. A simplified model of the structure is adopted. Removal of parts of the dam
cross-section is assumed to occur: the effects of the extent of damage is discussed on the
bases of the tension generated within the body of the dam.
Ductile-Fragile Transition: A Novel Comparison Between Fracture Mechanics of Materials and Framed Structures
Get PDFThis paper deals with the issue of structural collapse considering an analogy between ductile-brittle transition of materials, taking into account the current literature which also considers the number of fragility and the stress intensification factor in the presence of crack, with extension on a larger scale involving framed structures subjected to increasing vertical loads. It is evaluated the ductile-fragile transition in relation to concrete frames with different structural hierarchy (2x2, 5x5, 11x11)