Advances in Science and Technology Vol. 163

Abstract: Inland waterway shipbuilding plays a pivotal role in facilitating the transportation of goods and passengers in numerous regions worldwide. To meet the ever-evolving demands of efficiency, safety, and sustainability, shipbuilders constantly seek to enhance the quality and performance of their vessels. Welding, a critical component of shipbuilding, has garnered significant attention due to its potential to introduce deformations and residual stresses, which can adversely affect structural integrity and long-term performance. This study presents preliminary research aimed at comprehensively understanding the influence of deformations and residual stresses after the welding process in inland waterway shipbuilding. The preliminary findings of this research highlight the significant influence of welding parameters, material properties, and welding sequences on the magnitude and distribution of deformations and residual stresses in inland waterway shipbuilding. These findings have implications for ship design, fabrication, and inspection procedures. By mitigating deformation and residual stress-related issues, shipbuilders can enhance the structural integrity, safety, and operational efficiency of their vessels.

Abstract: Magnesium along with its alloy has garnered significant attention for potential utilization in biomedical applications, owing to its biodegradable and biocompatible characteristics. This paper aims to present preliminary research on the microwave heating of a concrete crucible designed to ensure the proper temperature for the sintering of magnesium alloy. Due to the reflection coefficient of microwaves by the magnesium alloy, the utilization of a microwave susceptor becomes imperative for effective heating. The research primarily focuses on modeling the temperature distribution within the concrete crucible to ensure a consistent level of heat for the sintering process of the magnesium alloy. As a result of the modeling process, temperatures up to 298°C have been achieved across a broad range of microwave power inputs (600-1200 W).

Abstract: This article provides an overview of Direct Energy Deposition – Arc technology (DED-Arc), also known as Wire Arc Additive Manufacturing (WAAM), which involves the deposition of metal wire using an arc power source and a CNC or robotic manipulator. The high deposition rate of WAAM justifies its use for the manufacturing of small to large-size components with lower resolution and less complex geometry. However, the use of wire as feedstock in the WAAM process has certain advantages and disadvantages, which are explained in detail. The WAAM specialties are in-situ alloying and the production of functionally graded materials (FGMs). Various sensors, path planning, process control, and FEM simulation from WAAM are used to reduce material and energy consumption and make the process more sustainable. Post-processing techniques are also discussed as a method of improving the quality of the final product. Finally, the prospects of the WAAM process are presented.

Abstract: Determining past trends is a rather arbitrary operation, despite that the processes that have already taken place "only" need to be systematized, not predicted. The experience required for this work is only sufficient if the author has experience in the specific field. In this thesis, the author undertakes to present some trends in the field of material science and material technology that are typical of the processes that have taken place in recent decades. Since it is only about areas in which the author has his own, personal experience, it is necessary that this selection is completely random. The specialized areas in question are: the development of structural materials in bridge construction, the use of stainless steels, structural materials in the automotive industry and vehicle lighting, as well as in the production of metal matrix composites and materials for coronary stents.

Abstract: In this article an x-ray method of analysing modified vehicle series is presented. A method of electrochemical analysis of a vehicle's series was also used beforehand to highlight its modification. This method is particularly useful in identifying and characterizing changes in the structural or material composition of vehicles that have undergone modifications. Before discussing the x-ray analysis, the article also mentions the use of electrochemical analysis as an initial approach to highlight modifications in vehicle series. Finally, the advantages and disadvantages of the x-ray analysis method are presented.

Abstract: Robot welding is the utilization of industrial robots to automate and execute welding tasks. The robots are outfitted with specialized welding tools and equipment that allow them to manage the welding flame and produce welds with accuracy and uniformity. Robot welding has several benefits, such as enhanced efficiency, superior weld quality, and decreased labor expenses. It is extensively utilized in diverse industries such as automobile production, aerospace, fabrication, and others. The paper deals with the change that will occur at the production level in the field of welding engineering.

Abstract: Photovoltaic (PV) systems have gained significant attention as a viable and sustainable source of electricity generation. This paper provides an examination of the efficiency of four PV systems installed across the South West and West regions of Romania, exploring the underlying mechanisms, influencing factors, and strategies for optimization. The solar data and the power generated by the PV systems are systematically collected and analysed. High PV system efficiency has several significant environmental and economic benefits: reduced greenhouse gas emissions, energy independence, cost savings and job creation. The aim is to contribute to the understanding and advancement of PV technology for a cleaner and more sustainable energy future.

Abstract: The construction sector is one of the major consumers of energy and non-renewable natural resources, but also an important factor in increasing global warming through the production of greenhouse gases. It is essential to involve and prioritize the energy renovation of buildings, both to increase interior comfort and to reduce the impact on the environment (40% of total energy consumption, 36% of total CO2 emissions, 25-30% of total waste generated) (Valverde et al., 2013) [1]. Amending Directive (EU) 2018/844 requires EU countries to develop, by 2050, long-term renovation strategies to support the renovation of residential and non-residential buildings into a building stock with a high level of energy efficiency and decarbonisation. [2]. The purpose of the work is to provide recommendations, to establish the energy performance of a public building-secondary school-x and to substantiate the solutions and measures for its rehabilitation. The objectives of this paper are to study and develop tools for analyzing the energy optimization options of the structural components of buildings and to formulate an efficient and easily approachable framework-procedure for the evaluation of the decision-making process of increasing the energy efficiency of buildings. The energy performance of the building is determined according to a calculation methodology and is expressed by one or more numerical indicators that are calculated taking into account the thermal insulation, the technical characteristics of the building and installations, the design and location of the building in relation to external climatic factors, exposure to the sun and the influence of neighboring buildings, own sources of energy production and other factors, including the indoor climate of the building, which influence the energy requirement. The techniques used consist in the determination of heat losses through glazed surfaces and opaque surfaces. The results showed that through the package of measures applied, the primary energy consumption was reduced by 56.38%, the annual primary energy consumption 94.49 [kwh/m2, year], and the CO2 equivalent emission index = 18.44 [kgCO2/m2, year].

Abstract: The Danube River is the most valuable ecosystem in the European natural environment. One third of the surface of the basin and half of the length of the navigable course is found on the territory of Romania. The paper aims to identify the sources of pollution existing on the Romanian sector of the Danube and the effects produced by them with an impact on altering the quality of the Danube water. The data submitted are prepared on the basis of information made available by the Territorial Administrative Units having jurisdiction sectors of the Danube River and observations, records existing in the databases of the competent authorities. Thus, the Danube is a waterway, a source of drinking water supply for the population, an important source for the irrigation system in agriculture, a source of water supply for various systems and installations in industry and last but not least, the collector of wastewater from these activities. In addition, the Danube is also the natural habitat for many species of animals and plants. The sources of pollution affecting the Danube's water quality are the most diverse and come from all fields: naval transport, industrial production units, agriculture, human agglomerations. The investments made during the last years in the modernization of existing treatment plants and the construction of new ones in the localities bordering the Danube, lead to a decrease in pollution by treating wastewater collected and processed in these plants. The consistent monitoring and in accordance with the legal provisions in force of all potentially polluting activities, the optimization of loading and unloading operations of goods in the terminals on the Romanian territory of the Danube, the handling and transport of dangerous goods in compliance with the most demanding requirements has led to an increase in the quality of the Danube water, which is of good quality, as appreciated by specialists in the field. The modernization of inland waterway vessels, continuous monitoring of the quality of wastewater discharged by industrial production units, the quality of domestic wastewater from human agglomerations, the consumption of pesticides in agriculture contributed to achieving this quality, among others.