2026

Permanent URI for this collectionhttps://repository.iuls.ro/handle/20.500.12811/6237

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listelement.badge.access-status Open Access ,
Enhancing Dielectric, Electrical, and Gas Sensing Properties of CaFeO3−δ Through Sintering Temperature Optimization
(MDPI, 2026-03-17) Benatia, Amina; Gouitaa, Najwa; Turcan, Ina; Gheorghiu, Felicia; Ursu, Laura-Elena; Leontie, Liviu; Mitoseriu, Liliana; Ahjyaje, Fatima Zahra; Lamcharfi, Taj-dine; Abdi, Farid
This research aims to investigate the modifications of the structural, dielectric, and sensing properties of CaFeO3−δ ceramics produced by solid-state reaction induced by varying sintering temperatures in the range of 1000–1200 °C. A single crystallographic orthorhombic (Pcmn) structure was revealed by X-ray diffraction with Rietveld analysis, both for the powders and sintered ceramics, irrespective of the sintering temperature. The increase in the sintering temperature induces better densification and a larger grain size. Dielectric measurements reveal a pronounced enhancement of the relative permittivity, reaching 2 × 105 at 1 kHz and 330 °C for the sample sintered at 1200 °C/4 h. This composition also displays the highest electrical conductivity, 0.4 S/m at 1 MHz. Cole–Cole analysis indicates a clear deviation from ideal Debye behavior, while the relaxational features of the dielectric permittivity suggest a strong correlation between the dielectric response and Fe-related conduction mechanisms. Gas sensing tests show that the ferrite ceramics exhibit consistent ethanol response trends. The ceramic sintered at 1200 °C/4 h achieved the highest sensitivity, of 56.28%, which can be attributed to its higher density, larger ceramic grains, and reduced low-frequency conductivity. The CaFeO3−δ ceramic sintered at 1200 °C/4 h shows a combination of high permittivity, enhanced conductivity, and strong ethanol sensitivity, making it a promising material for dielectric components, capacitive devices, and gas sensing applications.
listelement.badge.access-status Open Access ,
Field Performance andWear Behavior of Atmospheric Plasma Spraying (APS) Coated Discs Used in Agricultural Disc Harrows
(MDPI, 2026-01-01) Arsenoaia, Vlad-Nicolae; Munteanu, Corneliu; Lupu, Fabian-Cezar; Istrate, Bogdan; Benchea, Marcelin; Melnic, Iurie
The wear performance of coated and uncoated harrow discs was evaluated under real agricultural field conditions in order to assess the long-term effectiveness of three atmospheric plasma spraying (APS) systems: a Cr2O3–SiO2–TiO2 ceramic coating, a WC/W2C–Co carbide coating, and a Co–Cr–Ni–W–C alloy coating. In contrast to most previous studies focused on laboratory testing or short-term trials, the present work provides a comparative long-term field evaluation over 50 ha per disc (1000 ha total) under identical operating conditions in quartz-rich Argic Luvisol soil. Disc wear was quantified through periodic mass-loss and diameter measurements, complemented by microstructural and SEM analyses. The uncoated disc exhibited the most severe degradation, with a total mass loss of approximately 700 g and rapid acceleration of wear after the first 5–10 ha. The ceramic-coated disc showed the highest durability, limiting mass loss to approximately 390 g, corresponding to a reduction of about 44%, and maintaining the largest residual diameter after field operation. The Co-based alloy provided intermediate performance (~16% mass-loss reduction), while the carbide coating showed limited improvement (~7% reduction) due to microcracking and weak carbide–binder interfaces. The results demonstrate that, under real field conditions, coating microstructural integrity is more critical than nominal hardness, and highlight the superior effectiveness of ceramic APS coatings for extending disc service life in abrasive agricultural soils.
listelement.badge.access-status Open Access ,
Evaluation of Nutraceutical Properties of Fruits Derived from Some Wild‑Growing Plant Species (Sambucus nigra L., Rubia tinctorum L., Phytolacca americana L. and Sambucus ebulus L.)
(MDPI, 2026-04-07) Lungoci, Constantin; Motrescu, Iuliana; Vlase, Laurian; Puiu, Ioan
Wild-growing plant species are sustainable, cost-effective and underexploited sources for bioactive compounds with great nutraceutical potential. In this work, we analysed the fruits of several wild plant species: Sambucus nigra L., Rubia tinctorum L., Phytolacca americana L. and Sambucus ebulus L. Liquid chromatography coupled with mass spectrometry revealed diverse concentrations of phenolic acids, with the highest values observed for rutoside (22.183 µg mL−1) and isoquercitrin (11.663 µg mL−1) in S. nigra L., chlorogenic acid (7.422 µg mL−1) in R. tinctorum L., caftaric acid (4.942 µg mL−1) in P. americana L., and quercitrin (1.380 µg mL−1) and 4-O-caffeoylquinic acid (1.196 µg mL−1) in S. ebulus L. The spectrophotometric analysis showed that S. nigra L. had the highest concentration of total phenols (14.21 mg GAE g−1 FW) and the highest flavonoid content (8.07 mg QE g−1 FW). The lowest values were recorded for R. tinctorum L. (total phenols) and P. americana L. (flavonoids). The antioxidant activity was generally high, with the lowest value of 76.08% for S. nigra L. and over 90% for all other species, peaking at 93.25% for P. americana L. The Trolox Equivalent Antioxidant Capacity (TEAC) assay showed a similar pattern. S. ebulus L. and R. tinctorum L. exhibited the highest carbohydrate content and protein solubility, respectively. P. americana L. fruits had the highest ascorbic acid concentration, 0.136 mg g−1 FW. These results highlight the remarkable nutraceutical potential of certain wild fruits, identifying them as rich and cost-effective sources of bioactive compounds, particularly antioxidants, with promising perspectives for future studies on their therapeutic potential.
listelement.badge.access-status Open Access ,
Synergistic Interactions and Short-Term Impact of Tillage Systems on Soil Physico-Chemical Properties and Organic Carbon Sequestration in North-Eastern Romania
(MDPI, 2026-01-10) Cakpo, Serginho Segla ; Rusu, Mariana; Ghelbere, Cosmin; Mihu, Gabriel-Dumitru; Aostăcioaei, Tudor-George; Boți, Ioan; Jităreanu, Gerard; Țopa, Denis-Constantin
Tillage practices regulate soil health by influencing soil’s physico-chemical qualities and its capacity to sequester organic carbon. Maintaining soil health contributes to ecosystem stability and fluidity in the soil–plant–atmosphere relationship. This study aimed to evaluate soil porosity (SP), aeration limit (SAL), soil capillary capacity (SCC), soil total capacity (STC), soil temperature (Ts), air temperature (Ta), nutrient availability, soil organic carbon (SOC), and soil organic matter (SOM) under three different tillage systems: no-tillage (NT), minimum tillage (MT), and conventional tillage (CT), based on a short-term field experiment. This research was conducted on Cambic Chernozem soil using a randomized complete block design with three replications. The results revealed a significant effect of tillage systems on all evaluated properties. SP reached a higher value under MT (60.01%), NT (56.74%) and CT (53.58%), respectively. This observation is similar with regard to SAL, SCC, and STC. It might be due to the reduced soil disturbance characteristics of conservation systems, thereby maintaining the soil’s natural state. There is a positive regression between these two properties across all three systems, with the highest R2 = 0.8308 observed under MT. The highest carbon stocks were recorded in NT (2.82%) and MT (2.91%) compared to 2.01% in CT at surface depths of 0–5 and 5–10 cm. This can be explained by the accumulation of organic residues and a reduction in their oxidation. Nutrient availability (TN, P, and K) increased at depths of 0–5 cm and 5–10 cm, with the highest values in conservation systems. Furthermore, the results demonstrate a significant relationship and positive synergy between soil depth, tillage practices, and key physical and chemical soil properties, especially carbon stock, across the two cropping seasons.
listelement.badge.access-status Open Access ,
Non-Thermal Plasma as Novel Environmentally Friendly Agricultural Biotechnology for Seed Treatment and Stimulation of Early Plant Growth
(MDPI, 2026-03-31) Motrescu, Iuliana; Lungoci, Constantin; Luchian, Camelia-Elena; Rîmbu, Cristina-Mihaela; Ciolan, Mihai-Alexandru; Calistru, Anca-Elena; Miron, Liviu-Dan; Jităreanu, Gerard
Modern agriculture faces significant challenges, such as population growth, the reduction in productive agricultural land, and, most importantly, climate change. To address these issues, non-thermal plasma treatment of seeds and plants has emerged as a promising alternative to conventional chemical-based methods. This advanced technology, a powerful chemical reactor in the gas phase, has various applications, from stimulating seed germination and plant growth to controlling pathogens. The effects of non-thermal plasma on seeds include morphological and chemical changes in the seed coat, increased permeability and water uptake, and the activation of some internal biochemical mechanisms. Studies have demonstrated improvements in germination, plant development, and the activation of internal biochemical mechanisms with the intensified production of secondary metabolites. Non-thermal plasma also contributes to reducing the microbial load, providing an effective and environmentally friendly method of disinfection. This review synthesises the current knowledge on non-thermal plasma sources used in plasma agricultural applications for seed treatments, emphasising that in some cases the exposure of seeds to such discharge stimulates germination and also promotes early seedling growth. In addition, it highlights reported biochemical and nutraceutical improvements, including changes in antioxidant capacity, phenolic content and other bioactive compounds which add considerable value to the resulting plants. Finally, the decontamination potential is discussed, along with results discussing the potential of NTP to decontaminate seeds, associated with an extension to the shelf-life of products and identifying key challenges and research gaps for implementing this technology in agricultural practices. The integration of this technology into modern agriculture, including vertical farms and hydroponic systems, opens up the prospect for more sustainable and productive agriculture. However, scaling up the process and optimising processing parameters remain important challenges that require further attention, research and technological development.
listelement.badge.access-status Open Access ,
Water Regime Effects on Phosphorus Mobility and the Performance of Liquid Phosphorus Fertilizers in Contrasting Soils
(MDPI, 2026-03-02) Răus, Lucian; Bolohan, Diana-Elena
The behavior of phosphorus (P) fertilizers in soil is governed not only by fertilizer solubility, but also by P mobility and vertical redistribution within the soil profile under contrasting water regime. This study aimed to investigate the combined effects of water regime, fertilizer type, and soil properties on the vertical redistribution of ammonium acetate–lactate extractable phosphorus (P-AL) in the surface soil layer under controlled pot conditions. Experiments were conducted using three soils with contrasting chemical properties: AC-LO (acidic loam, pH 5.9), NE-CL (neutral clay loam, pH 6.8), and AL-SL (alkaline sandy loam, pH 8.0). Four simulated rainfall regimes were applied at a constant rate of 25 mm day−1, corresponding to cumulative water inputs of 0 mm (W0), 50 mm (W50), 100 mm (W100), and 150 mm (W150). Fertilizer treatments included an unfertilized control (NF), a liquid NP 4–18 fertilizer applied at a low dose (L1), a liquid NP 4–18 fertilizer applied at a high dose (L2), and a solid NPK 15–15–15 fertilizer (S). Water regime exerted the strongest control on P mobility, with P-AL increasing by approximately 40–60% from W0 to W150, depending on soil type. In AC-LO, strong P fixation under low moisture minimized differences among fertilizer treatments, whereas under higher moisture (W100–W150), liquid fertilizers—particularly L2—resulted in P-AL levels approximately 10–30% higher than those of the solid fertilizer. In NE-CL, P mobility was moderate and, under W100–W150, L2 produced P-AL values approximately 10–15% higher than the solid fertilizer, promoting a more uniform P redistribution within the 2–8 cm layer. In AL-SL, the response under wet conditions depended on the water regime: at W100, L2 generated P-AL values comparable to the solid fertilizer, whereas at W150, L2 increased P-AL by approximately 11% relative to the solid form. Overall, the results indicate that soil chemical properties primarily regulate the extent of phosphorus redistribution, while water regime controls its intensity and fertilizer form influences the initial spatial configuration of P within the surface soil layer. The findings provide mechanistic insight into short-range phosphorus transport in soil, without allowing direct inferences regarding agronomic efficiency or crop response.
listelement.badge.access-status Open Access ,
Interannual Climatic Variability Modulates Biostimulant and Herbicide Effects on Yield and Seed Quality of White Lupin Under Rainfed Conditions
(MDPI, 2026-02-27) Velică, Florin; Puiu, Ioan; Simioniuc, Dănuț-Petru; Ghițău, Carmen-Simona; Robu, Teodor
White lupin (Lupinus albus L.) is increasingly promoted as a sustainable protein crop; however, the consistency of agronomic input responses under rainfed continental conditions remains insufficiently documented. This study evaluated the interannual consistency of a foliar amino acid-based biostimulant (Aminotop N) and herbicide-based weed control on morphological traits, grain yield, seed physical quality (thousand-seed weight and hectoliter mass), and seed nitrogen and crude protein concentration of white lupin (cv. Măriuca). A 2 × 2 factorial field experiment arranged in a randomized complete block design was conducted across two consecutive growing seasons (2024–2025). Two-way ANOVA revealed significant effects of year and significant year × treatment interactions for grain yield and seed physical traits (p ≤ 0.05), indicating season-dependent treatment responses. Statistically significant treatment differences were detected in 2024, whereas no differences were observed among treatments in 2025. Seed total nitrogen concentration and crude protein content remained statistically stable across treatments and years. Principal component analysis explained 98.2% of total variance, with the first component primarily separating years rather than treatments. These results demonstrate that treatment effects were not consistently expressed across seasons and highlight the necessity of multi-year validation when assessing agronomic input effectiveness in white lupin under rainfed conditions.

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