Universitatea Danubius Galati

Duralumin 2024-T351 is an alloy characterized by a good mechanical strength, relatively high hardness and corrosion resistance frequently used in the aeronautical, automotive, defense etc. industries. In this paper, the variation of axial forces and torques when drilling aluminum alloy 2024-T351 was investigated, analyzing the measured values for different cutting regimes. Experimental data on the forces and moments generated during the drilling process were collected using specialized equipment, and these data were preprocessed and analyzed using MatLab R218a. The experimental plan included 27 combinations of the parameters of the cutting regime (cutting depth, cutting speed, and feed), for which energetic cutting parameters were measured, the axial force and the torsion moment, respectively Based on these data, a neural network was trained, using the Bayesian regularization algorithm, in order to predict the optimal values of the cutting energy parameters. The neural model proved to be efficient, providing predictions with a relative error below 10%, indicating a good agreement between measured and simulated values. In conclusion, neural networks offer an accurate alternative to classical analytical models, being more suitable for materials with complex behavior, such as aluminum alloys.

Homeopathy was founded some two hundred years ago by Dr Samuel Christian Hahnemann. Over time, it has grown to be among the most frequently used forms of alternative medicine in Europe and the USA. It is underpinned by the principle of ‘like cures like’, where highly diluted substances are used for therapeutic purposes, by producing similar symptoms to when the substance is used in healthy people. Many studies have been published on the value of homeopathy in treating diseases such as cancer, depression, psoriasis, allergic rhinitis, asthma, otitis, migraine, neuroses, allergies, joint disease, insomnia, sinusitis, urinary tract infections and acne, to name a few. We conducted a comprehensive review of the literature on homeopathy and evaluated its effectiveness in clinical practice. While there is evidence of the clinical benefits of homeopathy, its formal application requires more rigorous randomised controlled trials.

More than 37,000 km of waterways connect hundreds of cities and industrial regions in Europe. These inland waterways play an important role in the transport of goods. The EU-funded PLOTO project aims at studying the resilience of the infrastructure of inland waterways and that of the connected land infrastructure. The main objective of the project is to ensure reliable network availability under unfavourable conditions (e.g. extreme weather, accidents, as well as other kind of hazards). PLOTO utilises high-resolution modelling data to assess climatic risk and focuses on the design of an innovative planning tool that can run ‘what if’ impact/risk/resilience assessment scenarios.

Conventional passive packaging plays a crucial role in food manufacturing by protecting foods from various external influences. Most packaging materials are polymer-based plastics derived from fossil carbon sources, which are favored for their versatility, aesthetic appeal, and cost-effectiveness. However, the extensive use of these materials poses significant environmental challenges due to their fossil-based origins and persistence in the environment. Global plastic consumption for packaging is expected to nearly triple by 2060, exacerbating the ecological crisis. Moreover, globalization has increased access to a diverse range of foods from around the world, heightening the importance of packaging in providing healthier and safer foods with extended shelf life. In response to these challenges, there is a growing shift to eco-friendly active packaging that not only protects but also preserves the authentic qualities of food, surpassing the roles of conventional passive packaging. This article provides a comprehensive review on the viability, benefits, and challenges of implementing bio-based biodegradable polymers in active food packaging, with the dual goals of environmental sustainability and extending food shelf life.

Semiconductors are a rampant ICT sector utilized in everyday life for electronic devices. This industry provides plentiful income to multinational corporations (MNCs) but has been put in the spotlight for its tremendous social, ecological, and political impact. The figures become dramatic in sub-Saharan Africa and developing countries, which have abundant resources but poor working conditions and abrupt environmental degradation. In this interplay, rare earths have become leading assets for companies and governments and are highly debated for their controversial nature; thereby, corporate social responsibility (CSR) and environmental practices turn pivotal. This work aims to connect the bountiful industrial sector of semiconductors with rare earths governance and CSR. To this end, this inquiry critically scrutinizes these three assets, analyzing the case study of onsemi as a business case and launching selected strategic and policy perspectives. This paper reviews these three concepts and conducts a content analysis on onsemi CSR Report and Annual Sustainability Report. The literature review emphasizes the increasing importance of these three topics within the mineral economics and sustainability research. The company analyzed produced cogent reports but supplementary information is needed to better understand its results within the semiconductors and extractive industry. This may help determining key achievements and areas for improvements in the private sector for REE sustainability, CSR and environment, social and governance (ESG) results and disclosure. The availability and governance of rare earths will determine decisive sustainability directions of utmost priority for geopolitical equilibria. The undertaken corporate and institutional strategies will lean toward dramatically diverse scenarios.

This article introduces the Risk Balancing Frontier (RBF), a new portfolio boundary in the absolute risk-total return space: the RBF arises when two risk indicators, the Tracking Error Volatility (TEV) and the Value-at-Risk (VaR), are both constrained not to exceed pre-set maximum values. By focusing on the trade-off between the joint restrictions on the two risk indicators, this frontier is the set of all portfolios characterized by the minimum VaR attainable for each TEV level. First, the RBF is defined analytically and its mathematical properties are discussed: we show its connection with the Constrained Tracking Error Volatility Frontier (Jorion in Financ Anal J, 59(5):70–82, 2003. https://doi.org/10.2469/faj.v59.n5.2565) and the Constrained Value-at-Risk Frontier (Alexander and Baptista in J Econ Dyn Control, 32(3):779–820, 2008. https://doi.org/10.1016/j.jedc.2007.03.005) frontiers. Next, we explore computational issues implied with its construction, and we develop a fast and accurate algorithm to this aim. Finally, we perform an empirical example and consider its relevance in the context of applied finance: we show that the RBF provides a useful tool to investigate and solve potential agency problems.

The purpose of this study is to evaluate the corrosion resistance in natural seawater (Năvodari area) of two types of low-alloy carbon steels BVDH36 and LRAH36 by electrochemical methods. The electrochemical methods used were the evolution of the free potential (OCP), electrochemical impedance spectroscopy (EIS), polarization resistance (Rp) and corrosion rate (Vcorr), potentiodynamic polarization (PD), and cyclic voltammetry (CV). The studies were completed by ex situ characterization analyzes of the studied surfaces before and after corrosion such as: optical microscopy, scanning electron microscopy and X-ray diffraction analysis. The results of the study show us that the polarization resistance of the low-alloy carbon steel BVDH36 is higher compared to the polarization resistance of the low-alloy carbon steel LRAH36. It is also observed that with the increase in the immersion time of the samples in natural seawater, the polarization resistance of the BVDH36 alloy increases over time and finally decreases, and for the carbon steel LRAH36 the polarization resistance increases.

The FOR-FREIGHT (Flexible, multi-mOdal and Robust FREIGHt Transport) project represents a pioneering initiative aimed at revolutionizing multimodal logistics by optimizing transport capacity and enhancing sustainability and efficiency. This paper delves into the project's overarching objectives, methodologies, and anticipated impacts. With a primary focus on developing innovative solutions seamlessly integrated into existing logistics systems, FOR-FREIGHT strives to diminish the average cost of freight transport. The project's unique approach encompasses a comprehensive, end-to-end optimization of multimodal logistics services, addressing challenges prevalent in airports, ports, inland terminals, and logistics nodes. Central to FOR-FREIGHT's success is the creation of a cloud-based platform, combining IoT, AI/ML, and Big Data Management, designed to streamline logistics processes and facilitate decision-making. The paper also emphasizes the integration of legacy systems, ensuring the project's applicability to real-world scenarios. Furthermore, FOR-FREIGHT envisions an open marketplace and standardized interfaces, fostering collaboration and interoperability across diverse stakeholders. As the project advances, it promises to not only redefine multimodal logistics practices but also contribute to the establishment of sustainable and efficient standards within the industry.

In the literature, it is well known that there is a bidirectional causality between economic growth and energy consumption. This is why it is crucial to forecast energy consumption. In this study, four deep learning models, i.e., Long Short-Term Memory (LSTM), stacked LSTM, bidirectional LSTM, and Gated Recurrent Unit (GRU), were used to forecast energy consumption in Brazil, Canada, and France. After a training test period, the performance evaluation criterion, i.e., R², mean square error, root mean square error, mean absolute error, and mean absolute percentage error, was performed for the performance measure. It showed that GRU is the best model for Canada and France, while LSTM is the best model for Brazil. Therefore, the energy consumption prediction was made for the 12 months of the year 2017 using LSTM for Brazil and GRU for Canada and France. Based on the selected model, it was projected that the energy consumption in Brazil was 38 597.14–38 092.88, 63 900–4 800 000 GWh in Canada, and 50 999.72–32 747.01 GWh in France in 2017. The projected consumption in Canada was very high due to the country’s higher industrialization. The results obtained in this study confirmed that the nature of energy production will impact the complexity of the deep learning model.

Caffeine (CAF) has been shown to be an effective ergogenic aid in enhancing sports performance, including vertical jump (VJ), sprint, balance, agility, and freestyle swimming performance (FSP). However, whether acute CAF supplementation improves FSP in moderately trained female swimmers has not been well documented. Therefore, this study aimed to investigate the effects of CAF intake on vertical jump, balance, auditory reaction time (ART), and swimming performance in female swimmers. In a double-blind, cross-over design, eight moderately trained female swimmers (age: 21.3 ± 1.4 years, height: 161.2 ± 7.1 cm, body mass: 56.3 ± 6.7 kg, body mass index (BMI): 21.9 ± 1.3 kg/m², and habitual CAF intake: 246.4 ± 111.4 mg/day) ingested caffeine (CAF) (6 mg/kg) or a placebo (PLA) 60 min before completing VJ, balance, ART, and 25/50 m FSP. CAF supplementation resulted in a significantly lower time both in 25m (p = 0.032) and 50m (p = 0.033) FSP. However, CAF resulted in no significant difference in VJ, ART, and RPE (p > 0.05). Balance test results showed a non-significant moderate main effect (d = 0.58). In conclusion, CAF seems to reduce time in short-distance swimming performances, which could be the determinant of success considering the total time of the race. Thus, we recommend coaches and practitioners incorporate CAF into swimmers’ nutrition plans before competitions, which may meet the high performance demands.

The entrance in the Sulina channel in the Black Sea is the target area of this study. This represents the southern gate of the seventh Pan-European transport corridor, and it is usually subjected to high navigation traffic. The main objective of the work is to provide a more comprehensive picture concerning the past and future expected dynamics of the environmental matrix in this coastal area, including especially the extreme wind and wave conditions in connection with the possible navigation risks. The methodology considered assumes analyses performed at three different levels. First, an analysis of some in situ measurements at the zero-kilometer point of the Danube is carried out for the 15-year period of 2009–2023. Together with the maximum wind speed and the maximum value of the wind gusts, the water level variation was analyzed at this point. As a second step, the analysis is based on wind speed data provided by regional climate models. Two periods, each spanning 30 years, are considered. These are the recent past (1976–2005), when comparisons with ERA5 reanalysis data were also performed, and the near future (2041–2070), when two different models and three climate scenarios were considered. The focus was on the extreme wind speed values, performing comparisons between the past and future expected extreme winds. Finally, the third analysis is related to the wave conditions. Thus, using as a forcing factor each of the wind fields that was previously analyzed, simulations employing a spectral wave model were carried out. The wave modeling system was focused using three different computational domains with increasing resolution towards the target area, and the nearshore wave conditions were evaluated. The results show that both the extreme wind and wave conditions are expected to slightly increase in the future. Especially in the wintertime, strong wind fields are often expected in this area, with wind gusts exceeding more than 70% of the hourly average wind velocity. With regard to the waves, due to the complex nearshore phenomena, considerable enhancements in terms of significant wave heights are induced, and there is also an elevated risk of the occurrence of rogue waves. This work is still ongoing, and taking into account the high navigation risks highlighted, the next step would be to elaborate the risk assessment of severe shipping conditions, particularly related to the likelihood or probability of adverse conditions with the potential of generating hazardous situations in this coastal environment.

This research is a reflection on the new challenges in former European communist countries in three areas of gender equality. The analysis employs the gender disparity index (GDI), which encompasses life expectancy, education, and income indices, each equally weighted by gender. The former communist states are categorized into two clusters: the first comprising European Union (EU) member states, and the second consisting of non-EU member states or those in the integration process. The findings indicate pervasive gender-based inequalities across the former European communist bloc. This study offers critical insights for countries seeking EU accession, highlighting the need for targeted policies to address gender disparities in multiple domains. Contrary to the hypothesis positing a connection between feminine cultural values and gender egalitarian practices, the data do not support this assertion. The implications of this research are particularly pertinent for aspiring EU member states, who must navigate issues of monopolism while striving to establish effective principles of business efficiency.

This paper recovers 1-soliton solutions to the dispersive concatenation model that comes with power law of self-phase modulation. The method of undetermined coefficients has made this retrieval possible. The parameter constraints are listed for the existence of the solitons. While a full spectrum of solitons is enumerated and exhibited, it is proved that dark 1-solitons exist only for Kerr law of nonlinear refractive index change.

When a severe plastic deformation (SPD) process is performed at high temperatures, it becomes more versatile. Designed originally for the bulk nanoconstruction of hard-to-deform alloys, high-speed high-pressure torsion (HSHPT) is an SPD method used in this research for assembling multiple layers of shape memory nanocomposites. Three hard-to-deform magnetic alloys in the cast state were used. Soft magnetic shape memory alloys, NiFeGa and FePdMn, and a potentially hard magnetic alloy, CoZr, were assembled in various composites. Both grain refinement and strong layer bonding were achieved in ZrCo/FePdMn and ZrCo/NiFeGa composites in seconds. The very short SPD time is specific to HSHPT because of the intense friction that occurs under high pressures, which generates huge amounts of heat. After SPD, the temperature rises in bulk material like a pulse, being dissipated mostly through heat conduction. The SPD parameters were carefully controlled with an advanced automation system using a programmable logic controller. Nevertheless, the major drawbacks of high-pressure torsion were overcome, and large SPD discs were obtained. Various investigation techniques (optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and atomic force microscopy) show well-defined interfaces as well as a fine and ultrafine structure.

Climate change efect mitigation is a critical priority for top leaders and communities around the globe. Human-induced environmental issues are afecting humankind’s standard of living and development potential and the planetary boundaries. Sustainability objectives aim to enhance environmental quality and ensure sustainable development for all by eliminating social inequalities. This study examines the complex relationships between demographic features, foreign direct investment, technological innovation, and ecological footprint, emphasizing the relevance of population aging, population density, and urbanization in this context. The research uses a selection of emerging European economies during 1995–2018. The reasons for countries’ selection are related to the increasing rate of population aging in European countries, the attractiveness for foreign direct investment, the economic growth, and the technological advancement potential these emerging countries possess. In order to investigate the long-run relationship between the selected variables, the study tests the cross-section dependence, homogeneity, and cointegration and uses Konya tests to determine panel causality. Based on Konya methodology, diferences between countries in the panel are evidenced and discussed accordingly. Our fndings confrm the long-run relationship between environment, technological innovation, population aging, and FDI. The results of this research are highly relevant for policymakers in selected countries for identifying the set of correlations and the relevance of various variables in such national economies. Demographic features such as population aging and population density are critical for Europe, and the results show the impact on the ecological footprint.

This paper aims to investigate the relationship between air pollution (PM2.5) and a collection of features related to urban areas economic welfare and social-wellbeing based on data collected from a number of 15 European capitals, for a seven years' period (2010-2017). The empirical analysis describes the correlation between the particulate pollution and welfare features in selected urban areas. Moreover, the PM2.5 pollutions may affect the economic and social development of these areas as, both entrepreneurs and population are inclined to relocate for a healthier environment. The models emphasize aspects related to the impact of PM 2.5 on different dimensions as follows: real estate rent values and land prices, restaurants food prices, community economic development, human welfare, as well as urban traffic. From the various correlations we have also discovered that for the urban areas included in the research, at early stages urbanization has the highest impact on air pollution. The findings of this study may offer hints for decision makers for their social and economic policy options. A clean urban environment will attract more skilled employees seeking for economic, social and environmental wellbeing. If the urban agglomerations authorities will fail to mitigate properly the air pollution issues the wellbeing will decrease along with the willingness of urban population to stay in such areas.