Stefan Mihai Petrea

Prof. Stefan Mihai Petrea

''Dunărea de Jos'' University of Galați
orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Verified
Journal Article
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ISIra-Adeline Simionov
Ira-Adeline Simionov
VCVictor Cristea
Victor Cristea
Stefan Mihai PetreaStefan Mihai Petrea
Stefan Mihai Petrea
MAMogodan Alina
Mogodan Alina
MNMircea Nicusor Nicoara
Mircea Nicusor Nicoara
Caterina FaggioCaterina Faggio
Caterina Faggio
This study investigates the influence of gender in the bioconcentration of essential and nonessential elements in different parts of Black Sea turbot (Psetta maxima maeotica) body, from an area considered under high anthropogenic pressure (the Constanta City Black Sea Coastal Area in Romania). A number of 13 elements (Ca, Mg, Na, K, Fe, Zn, Mn, Cu, Ni, Cr, As, Pb and Cd) were measured in various sample types: muscle, stomach, stomach content, intestine, intestine content, gonads, liver, spleen, gills and caudal fin. Turbot adults (4–5 years old) were separated, according to their gender, into two groups (20 males, 20 females, respectively), and a high total number of samples (1200 from both groups) were prepared and analyzed, in triplicate, with Flame Atomic Absorption Spectrometry and High-Resolution Continuum Source Atomic Absorption Spectrometry with Graphite Furnace techniques. The results were statistically analyzed in order to emphasize the bioconcentration of the determined elements in different tissues of wild turbot males vs. females, and also to contribute to an upgraded characterization of the Romanian Black Sea Coast, around Constanta City, in terms of heavy metals pollution. The essential elements Mg and Zn have different roles in the gonads of males and females, as they were the only elements with completely different patterns between the analyzed groups of specimens. The concentrations of studied elements in muscle were not similar with the data provided by literature, suggesting that chemistry of the habitat and food plays a major role in the availability of the metals in the body of analyzed fish species. The gender influenced the bioaccumulation process of all analyzed elements in most tissues since turbot male specimens accumulated higher concentration of metals compared to females. The highest bioaccumulation capacity in terms of Ca, Mg, Na, Ni, As, Zn and Cd was registered in caudal fin, liver and intestine tissues. Also, other elements such as K, Fe, Cu and Mn had the highest bioaccumulation in their muscle, spleen, liver and gills tissues. The concentrations of toxic metals in Black Sea turbot from this study were lower in the muscle samples compared with the studies conducted in Turkey, suggesting that the anthropogenic activity in the studied area did not pose a major impact upon the habitat contamination.

6 December 2022 in Sensors
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Journal Article
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DMDan Munteanu
Dan Munteanu
DMDiana Moina
Diana Moina
CZCristina Gabriela Zamfir
Cristina Gabriela Zamfir
Stefan Mihai PetreaStefan Mihai Petrea
Stefan Mihai Petrea
CSCristea Dragos Sebastian
Cristea Dragos Sebastian
NMNicoleta Munteanu
Nicoleta Munteanu
In the context of new geopolitical tensions due to the current armed conflicts, safety in terms of navigation has been threatened due to the large number of sea mines placed, in particular, within the sea conflict areas. Additionally, since a large number of mines have recently been reported to have drifted into the territories of the Black Sea countries such as Romania, Bulgaria Georgia and Turkey, which have intense commercial and tourism activities in their coastal areas, the safety of those economic activities is threatened by possible accidents that may occur due to the above-mentioned situation. The use of deep learning in a military operation is widespread, especially for combating drones and other killer robots. Therefore, the present research addresses the detection of floating and underwater sea mines using images recorded from cameras (taken from drones, submarines, ships and boats). Due to the low number of sea mine images, the current research used both an augmentation technique and synthetic image generation (by overlapping images with different types of mines over water backgrounds), and two datasets were built (for floating mines and for underwater mines). Three deep learning models, respectively, YOLOv5, SSD and EfficientDet (YOLOv5 and SSD for floating mines and YOLOv5 and EfficientDet for underwater mines), were trained and compared. In the context of using three algorithm models, YOLO, SSD and EfficientDet, the new generated system revealed high accuracy in object recognition, namely the detection of floating and anchored mines. Moreover, tests carried out on portable computing equipment, such as Raspberry Pi, illustrated the possibility of including such an application for real-time scenarios, with the time of 2 s per frame being improved if devices use high-performance cameras.

12 May 2021 in Energies
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Florian NutaFlorian Nuta
Florian Nuta
Alina Cristina NutaAlina Cristina Nuta
Alina Cristina Nuta
CZCristina Gabriela Zamfir
Cristina Gabriela Zamfir
Stefan Mihai PetreaStefan Mihai Petrea
Stefan Mihai Petrea
DMDan Munteanu
Dan Munteanu
CSCristea Dragos Sebastian
Cristea Dragos Sebastian
The work at hand assesses several driving factors of carbon emissions in terms of urbanization and energy-related parameters on a panel of emerging European economies, between 1990 and 2015. The use of machine learning algorithms and panel data analysis offered the possibility to determine the importance of the input variables by applying three algorithms (Random forest, XGBoost, and AdaBoost) and then by modeling the urbanization and the impact of energy intensity on the carbon emissions. The empirical results confirm the relationship between urbanization and energy intensity on CO2 emissions. The findings emphasize that separate components of energy consumption affect carbon emissions and, therefore, a transition toward renewable sources for energy needs is desirable. The models from the current study confirm previous studies’ observations made for other countries and regions. Urbanization, as a process, has an influence on the carbon emissions more than the actual urban regions do, confirming that all the activities carried out as urbanization efforts are more harmful than the resulted urban area. It is proper to say that the urban areas tend to embrace modern, more green technologies but the road to achieve environmentally friendly urban areas is accompanied by less environmentally friendly industries (such as the cement industry) and a high consumption of nonrenewable energy.

17 January 2025 in Water
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Journal Article
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MPMarcel Daniel Popa
Marcel Daniel Popa
ISIra-Adeline Simionov
Ira-Adeline Simionov
Stefan Mihai PetreaStefan Mihai Petrea
Stefan Mihai Petrea
LGLucian Georgescu
Lucian Georgescu
GIGeorge Adrian Ifrim
George Adrian Ifrim
CICatalina Iticescu
Catalina Iticescu
Growing population, industrialisation, and demand for resources put pressure on the delicate balance of the planet’s ecosystems. From alternative sources of energy, healthier foods, cleaner water, and an overall more sustainable economy, the integration of microalgae in various industries, that otherwise are based on practices that hurt the environment, could be a successful solution. To reach that goal, further research is required on the complex relationship between microalgae and growth parameters (temperature, light intensity and spectrum, nutrient distribution, inhibiting factors, and so on). The scientific community successfully used microalgae to produce healthier foods, pigments, biofuel, animal fodder, methods for sequestering heavy metals, toxic compounds from water, and much more. In this review article, we approach the use of microalgae in municipal wastewater treatment, mainly for using nitrogen and phosphorous present in water as nutrients. Data were collected from articles published in the last 7 years (2018–2024). The results show that microalgae are very efficient at using N and P compounds from wastewater, as well as carbon, converting them in high-value substances (proteins, lipids, carbohydrates, etc.) with further applications in multiple industries.

1 February 2021 in Chemosphere
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Journal Article
Closed access
ISIra-Adeline Simionov
Ira-Adeline Simionov
DCDragos Sebastian Cristea
Dragos Sebastian Cristea
Stefan Mihai PetreaStefan Mihai Petrea
Stefan Mihai Petrea
AMAlina Mogodan
Alina Mogodan
MNMircea Nicoara
Mircea Nicoara
SSStefan-Adrian Strungaru
Stefan-Adrian Strungaru