The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science

Review on Ship Shaped Fish Farms

Costel UNGUREANU — 2024-03-15

This paper presents a review on ship shaped fish farms as a first step in the research and developing of a modular floating aquaculture platform based on inland river cargo barge design to be exploited under biosecurity and sustainability conditions in the Lower Danube region, aligned with the current sustainable development strategies of the blue economy outlined by the European Union.

Studies on the Conversion of a River Cargo Barge into a Floating Fish Farm

Costel UNGUREANU — 2024-03-15

This paper presents results of the research and developing of a modular floating aquaculture platform based on inland river cargo barge design to be exploited under biosecurity and sustainability conditions in the Lower Danube region, aligned with the current sustainable development strategies of the blue economy outlined by the European Union. The new design combines the capabilities of growing fish in modular tanks with the growing vegetables in recirculating systems in the greenhouse superstructure of the floating platform. The first step of this interdisciplinary and multidisciplinary research is a full naval architecture study, meaning both aerodynamically and strength calculation, as a starting point for the design and evaluation of the growing fish and cultivating vegetables systems.

An Overview on ZnO Reinforced Composites

Andreea Elena ONACHE (VIJAN) — 2024-03-15

Zinc oxide reinforced composites are a promising class of materials with a wide range of potential applications. By combining ZnO with other materials, scientists and engineers can achieve advanced functionalities that go beyond the properties of the individual components. The article offers to researchers and specialists an organized and thoughtful overview on outlining the impacts of composites, emphasis on ZnO nanoparticles reinforced composites.

Comparison of the Difference in Temperature Distribution on the Surface of Two Aluminum Alloys Welded by Friction Stir Welding in Different Regions at Different Linear and Rotational Speeds

Emad Toma KARASH — 2024-03-15

Friction stir welding is a modern process that is used commercially on a large scale in various industries and in many countries to connect materials together without reaching the melting point of the metal during the welding process, so it is called the solid-state welding process.
In this research, a three-dimensional mathematical model was designed for friction stir welding of aluminium alloys (AA7075-T6 & AA2024-O) with dimensions (100 x 100 x 6 mm), using (ANSYS 15.0) program to compare the results of temperature distribution with distance from the welding centre to the end of the welded piece, as well as the temperature distribution from the beginning of the welding process to its end, using different rotational speeds (900, 1050, 1200 rpm) and different linear speeds (20, 40, 60, 100 mm/min). In the beginning, the rotational speed was fixed and the linear speed was made variable, and then the linear speed was fixed and the rotational speed was changed.
The experimental results showed that the increase in the rotation speed of the welding tool leads to an increase in the temperatures on the surfaces of the models that were welded by the friction stir welding method. Among the other results obtained, it was found that the increase in the traveling speed of the trolley carrying the models when the stir welding process decreases the temperatures on the surface of the models when the welding process is performed. We note the convergence of the theoretical results with the applied results.

The Future of Construction from a Sustainable Materials Perspective

Simona STANCA — 2024-03-15

In the context of a growing global concern for the environment and sustainability, the construction industry is facing a key shift in the use of materials to reduce impact on the planet. The future of construction is increasingly taking shape under the imprint of material sustainability, a direction aimed at creating and using environmentally friendly and sustainable materials in the construction process. Today, the future of construction is closely linked to the use of sustainable materials and environmentally friendly practices. This paradigm shift in construction is driven by concerns about environmental impact and the need to reduce the carbon footprint of the construction industry. A sustainable approach is not just an option, but a necessity to ensure a better future and protect the environment for future generations. The future of construction under the imprint of material sustainability is a key topic in the context of global concerns about the environment and the limited resources of our planet.

Studies and Research on the Hardening of Some Industrial Benchmarks Through Laser Cladding

Simona BOICIUC — 2024-03-15

Industrial benchmarks are often subject to the wear and corrosion of the working environment. Laser cladding is a surface modification process that can improve their lifespan by ensuring hard, homogeneous, non-porous layers. The paper presents a series of experiments aimed at testing and calibrating the injection system used, making laser cladding with Ni-Cr-B-Fe-Al alloy on a series of industrial benchmarks and characterizing them in terms of hardness, thickness and microstructure.

Mathematical Modeling of the CuSn12 Alloy Sintering Process

Cristian ŞTEFĂNESCU — 2024-03-15

The purpose of this study is to use statistical methods, namely active experimental regression analysis, to forecast the size of the intergranular sintering bridge by mathematically modeling the sintering process as it is applied to the CuSn12 alloy powder. A first-order linear design method was used to characterize the correlation between the intergranular sintering bridge and the sintering parameters (temperature and sintering time). Using the free casting of the powder into graphite shapes, nine experiments were scheduled. Following sintering, the intergranular sintering bridge was evaluated metallographically using image analysis software. In order to optimize the sintering process, a regression equation has been established by mathematical modeling that predicts the size of the intergranular bridge with sintering parameters (temperature and time) with a high probability (>95%), within the experimental limits.